Rename "bundle extension" to "bootstrapper extension" for more consistency

Also renames WixToolet.BextUtil nupkg to WixToolset.BootstrapperExtensionApi.

119 files changed, 1082 insertions, 1087 deletions

diff --git a/src/api/api.cmd b/src/api/api.cmd
index 42453449..cae0cf5a 100644
--- a/src/api/api.cmd
+++ b/src/api/api.cmd
@@ -41,11 +41,13 @@ dotnet test ^
 @del "..\..\build\artifacts\WixToolset.Data.*.nupkg" 2> nul
 @del "..\..\build\artifacts\WixToolset.Extensibility.*.nupkg" 2> nul
 @del "..\..\build\artifacts\WixToolset.BootstrapperApplicationApi.*.nupkg" 2> nul
+@del "..\..\build\artifacts\WixToolset.BootstrapperExtensionApi.*.nupkg" 2> nul
 @del "%_L%\TestResults\api.trx" 2> nul
 @rd /s/q "%USERPROFILE%\.nuget\packages\wixtoolset.bextutil" 2> nul
 @rd /s/q "%USERPROFILE%\.nuget\packages\wixtoolset.data" 2> nul
 @rd /s/q "%USERPROFILE%\.nuget\packages\wixtoolset.extensibility" 2> nul
 @rd /s/q "%USERPROFILE%\.nuget\packages\wixtoolset.bootstrapperapplicationapi" 2> nul
+@rd /s/q "%USERPROFILE%\.nuget\packages\wixtoolset.bootstrapperextensionapi" 2> nul
 @exit /b
 
 :end
diff --git a/src/api/burn/bextutil/BextBundleExtensionEngine.cpp b/src/api/burn/bextutil/BextBootstrapperExtensionEngine.cpp
index 2c854817..a5e40c8e 100644
--- a/src/api/burn/bextutil/BextBundleExtensionEngine.cpp
+++ b/src/api/burn/bextutil/BextBootstrapperExtensionEngine.cpp
@@ -3,7 +3,7 @@
 #include "precomp.h"
 
 
-class CBextBundleExtensionEngine : public IBundleExtensionEngine
+class CBextBootstrapperExtensionEngine : public IBootstrapperExtensionEngine
 {
 public: // IUnknown
     virtual STDMETHODIMP QueryInterface(
@@ -18,9 +18,9 @@ public: // IUnknown
 
         *ppvObject = NULL;
 
-        if (::IsEqualIID(__uuidof(IBundleExtensionEngine), riid))
+        if (::IsEqualIID(__uuidof(IBootstrapperExtensionEngine), riid))
         {
-            *ppvObject = static_cast<IBundleExtensionEngine*>(this);
+            *ppvObject = static_cast<IBootstrapperExtensionEngine*>(this);
         }
         else if (::IsEqualIID(IID_IUnknown, riid))
         {
@@ -52,7 +52,7 @@ public: // IUnknown
         return 0;
     }
 
-public: // IBundleExtensionEngine
+public: // IBootstrapperExtensionEngine
     virtual STDMETHODIMP EscapeString(
         __in_z LPCWSTR wzIn,
         __out_ecount_opt(*pcchOut) LPWSTR wzOut,
@@ -60,8 +60,8 @@ public: // IBundleExtensionEngine
         )
     {
         HRESULT hr = S_OK;
-        BUNDLE_EXTENSION_ENGINE_ESCAPESTRING_ARGS args = { };
-        BUNDLE_EXTENSION_ENGINE_ESCAPESTRING_RESULTS results = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_ESCAPESTRING_ARGS args = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_ESCAPESTRING_RESULTS results = { };
 
         ExitOnNull(pcchOut, hr, E_INVALIDARG, "pcchOut is required");
 
@@ -72,7 +72,7 @@ public: // IBundleExtensionEngine
         results.wzOut = wzOut;
         results.cchOut = *pcchOut;
 
-        hr = m_pfnBundleExtensionEngineProc(BUNDLE_EXTENSION_ENGINE_MESSAGE_ESCAPESTRING, &args, &results, m_pvBundleExtensionEngineProcContext);
+        hr = m_pfnBootstrapperExtensionEngineProc(BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_ESCAPESTRING, &args, &results, m_pvBootstrapperExtensionEngineProcContext);
 
         *pcchOut = results.cchOut;
 
@@ -86,8 +86,8 @@ public: // IBundleExtensionEngine
         )
     {
         HRESULT hr = S_OK;
-        BUNDLE_EXTENSION_ENGINE_EVALUATECONDITION_ARGS args = { };
-        BUNDLE_EXTENSION_ENGINE_EVALUATECONDITION_RESULTS results = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_EVALUATECONDITION_ARGS args = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_EVALUATECONDITION_RESULTS results = { };
 
         ExitOnNull(pf, hr, E_INVALIDARG, "pf is required");
 
@@ -96,7 +96,7 @@ public: // IBundleExtensionEngine
 
         results.cbSize = sizeof(results);
 
-        hr = m_pfnBundleExtensionEngineProc(BUNDLE_EXTENSION_ENGINE_MESSAGE_EVALUATECONDITION, &args, &results, m_pvBundleExtensionEngineProcContext);
+        hr = m_pfnBootstrapperExtensionEngineProc(BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_EVALUATECONDITION, &args, &results, m_pvBootstrapperExtensionEngineProcContext);
 
         *pf = results.f;
 
@@ -111,8 +111,8 @@ public: // IBundleExtensionEngine
         )
     {
         HRESULT hr = S_OK;
-        BUNDLE_EXTENSION_ENGINE_FORMATSTRING_ARGS args = { };
-        BUNDLE_EXTENSION_ENGINE_FORMATSTRING_RESULTS results = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_FORMATSTRING_ARGS args = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_FORMATSTRING_RESULTS results = { };
 
         ExitOnNull(pcchOut, hr, E_INVALIDARG, "pcchOut is required");
 
@@ -123,7 +123,7 @@ public: // IBundleExtensionEngine
         results.wzOut = wzOut;
         results.cchOut = *pcchOut;
 
-        hr = m_pfnBundleExtensionEngineProc(BUNDLE_EXTENSION_ENGINE_MESSAGE_FORMATSTRING, &args, &results, m_pvBundleExtensionEngineProcContext);
+        hr = m_pfnBootstrapperExtensionEngineProc(BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_FORMATSTRING, &args, &results, m_pvBootstrapperExtensionEngineProcContext);
 
         *pcchOut = results.cchOut;
 
@@ -137,8 +137,8 @@ public: // IBundleExtensionEngine
         )
     {
         HRESULT hr = S_OK;
-        BUNDLE_EXTENSION_ENGINE_GETVARIABLENUMERIC_ARGS args = { };
-        BUNDLE_EXTENSION_ENGINE_GETVARIABLENUMERIC_RESULTS results = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLENUMERIC_ARGS args = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLENUMERIC_RESULTS results = { };
 
         ExitOnNull(pllValue, hr, E_INVALIDARG, "pllValue is required");
 
@@ -147,7 +147,7 @@ public: // IBundleExtensionEngine
 
         results.cbSize = sizeof(results);
 
-        hr = m_pfnBundleExtensionEngineProc(BUNDLE_EXTENSION_ENGINE_MESSAGE_GETVARIABLENUMERIC, &args, &results, m_pvBundleExtensionEngineProcContext);
+        hr = m_pfnBootstrapperExtensionEngineProc(BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_GETVARIABLENUMERIC, &args, &results, m_pvBootstrapperExtensionEngineProcContext);
 
         *pllValue = results.llValue;
 
@@ -163,8 +163,8 @@ public: // IBundleExtensionEngine
         )
     {
         HRESULT hr = S_OK;
-        BUNDLE_EXTENSION_ENGINE_GETVARIABLESTRING_ARGS args = { };
-        BUNDLE_EXTENSION_ENGINE_GETVARIABLESTRING_RESULTS results = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLESTRING_ARGS args = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLESTRING_RESULTS results = { };
 
         ExitOnNull(pcchValue, hr, E_INVALIDARG, "pcchValue is required");
 
@@ -175,7 +175,7 @@ public: // IBundleExtensionEngine
         results.wzValue = wzValue;
         results.cchValue = *pcchValue;
 
-        hr = m_pfnBundleExtensionEngineProc(BUNDLE_EXTENSION_ENGINE_MESSAGE_GETVARIABLESTRING, &args, &results, m_pvBundleExtensionEngineProcContext);
+        hr = m_pfnBootstrapperExtensionEngineProc(BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_GETVARIABLESTRING, &args, &results, m_pvBootstrapperExtensionEngineProcContext);
 
         *pcchValue = results.cchValue;
 
@@ -190,8 +190,8 @@ public: // IBundleExtensionEngine
         )
     {
         HRESULT hr = S_OK;
-        BUNDLE_EXTENSION_ENGINE_GETVARIABLEVERSION_ARGS args = { };
-        BUNDLE_EXTENSION_ENGINE_GETVARIABLEVERSION_RESULTS results = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLEVERSION_ARGS args = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLEVERSION_RESULTS results = { };
 
         ExitOnNull(pcchValue, hr, E_INVALIDARG, "pcchValue is required");
 
@@ -202,7 +202,7 @@ public: // IBundleExtensionEngine
         results.wzValue = wzValue;
         results.cchValue = *pcchValue;
 
-        hr = m_pfnBundleExtensionEngineProc(BUNDLE_EXTENSION_ENGINE_MESSAGE_GETVARIABLEVERSION, &args, &results, m_pvBundleExtensionEngineProcContext);
+        hr = m_pfnBootstrapperExtensionEngineProc(BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_GETVARIABLEVERSION, &args, &results, m_pvBootstrapperExtensionEngineProcContext);
 
         *pcchValue = results.cchValue;
 
@@ -211,12 +211,12 @@ public: // IBundleExtensionEngine
     }
 
     virtual STDMETHODIMP Log(
-        __in BUNDLE_EXTENSION_LOG_LEVEL level,
+        __in BOOTSTRAPPER_EXTENSION_LOG_LEVEL level,
         __in_z LPCWSTR wzMessage
         )
     {
-        BUNDLE_EXTENSION_ENGINE_LOG_ARGS args = { };
-        BUNDLE_EXTENSION_ENGINE_LOG_RESULTS results = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_LOG_ARGS args = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_LOG_RESULTS results = { };
 
         args.cbSize = sizeof(args);
         args.level = level;
@@ -224,7 +224,7 @@ public: // IBundleExtensionEngine
 
         results.cbSize = sizeof(results);
 
-        return m_pfnBundleExtensionEngineProc(BUNDLE_EXTENSION_ENGINE_MESSAGE_LOG, &args, &results, m_pvBundleExtensionEngineProcContext);
+        return m_pfnBootstrapperExtensionEngineProc(BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_LOG, &args, &results, m_pvBootstrapperExtensionEngineProcContext);
     }
 
     virtual STDMETHODIMP SetVariableNumeric(
@@ -232,8 +232,8 @@ public: // IBundleExtensionEngine
         __in LONGLONG llValue
         )
     {
-        BUNDLE_EXTENSION_ENGINE_SETVARIABLENUMERIC_ARGS args = { };
-        BUNDLE_EXTENSION_ENGINE_SETVARIABLENUMERIC_RESULTS results = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLENUMERIC_ARGS args = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLENUMERIC_RESULTS results = { };
 
         args.cbSize = sizeof(args);
         args.wzVariable = wzVariable;
@@ -241,7 +241,7 @@ public: // IBundleExtensionEngine
 
         results.cbSize = sizeof(results);
 
-        return m_pfnBundleExtensionEngineProc(BUNDLE_EXTENSION_ENGINE_MESSAGE_SETVARIABLENUMERIC, &args, &results, m_pvBundleExtensionEngineProcContext);
+        return m_pfnBootstrapperExtensionEngineProc(BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_SETVARIABLENUMERIC, &args, &results, m_pvBootstrapperExtensionEngineProcContext);
     }
 
     virtual STDMETHODIMP SetVariableString(
@@ -250,8 +250,8 @@ public: // IBundleExtensionEngine
         __in BOOL fFormatted
         )
     {
-        BUNDLE_EXTENSION_ENGINE_SETVARIABLESTRING_ARGS args = { };
-        BUNDLE_EXTENSION_ENGINE_SETVARIABLESTRING_RESULTS results = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLESTRING_ARGS args = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLESTRING_RESULTS results = { };
 
         args.cbSize = sizeof(args);
         args.wzVariable = wzVariable;
@@ -260,7 +260,7 @@ public: // IBundleExtensionEngine
 
         results.cbSize = sizeof(results);
 
-        return m_pfnBundleExtensionEngineProc(BUNDLE_EXTENSION_ENGINE_MESSAGE_SETVARIABLESTRING, &args, &results, m_pvBundleExtensionEngineProcContext);
+        return m_pfnBootstrapperExtensionEngineProc(BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_SETVARIABLESTRING, &args, &results, m_pvBootstrapperExtensionEngineProcContext);
     }
 
     virtual STDMETHODIMP SetVariableVersion(
@@ -268,8 +268,8 @@ public: // IBundleExtensionEngine
         __in_z_opt LPCWSTR wzValue
         )
     {
-        BUNDLE_EXTENSION_ENGINE_SETVARIABLEVERSION_ARGS args = { };
-        BUNDLE_EXTENSION_ENGINE_SETVARIABLEVERSION_RESULTS results = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLEVERSION_ARGS args = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLEVERSION_RESULTS results = { };
 
         args.cbSize = sizeof(args);
         args.wzVariable = wzVariable;
@@ -277,7 +277,7 @@ public: // IBundleExtensionEngine
 
         results.cbSize = sizeof(results);
 
-        return m_pfnBundleExtensionEngineProc(BUNDLE_EXTENSION_ENGINE_MESSAGE_SETVARIABLEVERSION, &args, &results, m_pvBundleExtensionEngineProcContext);
+        return m_pfnBootstrapperExtensionEngineProc(BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_SETVARIABLEVERSION, &args, &results, m_pvBootstrapperExtensionEngineProcContext);
     }
 
     virtual STDMETHODIMP CompareVersions(
@@ -287,8 +287,8 @@ public: // IBundleExtensionEngine
         )
     {
         HRESULT hr = S_OK;
-        BUNDLE_EXTENSION_ENGINE_COMPAREVERSIONS_ARGS args = { };
-        BUNDLE_EXTENSION_ENGINE_COMPAREVERSIONS_RESULTS results = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_COMPAREVERSIONS_ARGS args = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_COMPAREVERSIONS_RESULTS results = { };
 
         ExitOnNull(pnResult, hr, E_INVALIDARG, "pnResult is required");
 
@@ -298,7 +298,7 @@ public: // IBundleExtensionEngine
 
         results.cbSize = sizeof(results);
 
-        hr = m_pfnBundleExtensionEngineProc(BUNDLE_EXTENSION_ENGINE_MESSAGE_COMPAREVERSIONS, &args, &results, m_pvBundleExtensionEngineProcContext);
+        hr = m_pfnBootstrapperExtensionEngineProc(BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_COMPAREVERSIONS, &args, &results, m_pvBootstrapperExtensionEngineProcContext);
 
         *pnResult = results.nResult;
 
@@ -314,8 +314,8 @@ public: // IBundleExtensionEngine
     )
     {
         HRESULT hr = S_OK;
-        BUNDLE_EXTENSION_ENGINE_GETRELATEDBUNDLEVARIABLE_ARGS args = { };
-        BUNDLE_EXTENSION_ENGINE_GETRELATEDBUNDLEVARIABLE_RESULTS results = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_GETRELATEDBUNDLEVARIABLE_ARGS args = { };
+        BOOTSTRAPPER_EXTENSION_ENGINE_GETRELATEDBUNDLEVARIABLE_RESULTS results = { };
 
         ExitOnNull(pcchValue, hr, E_INVALIDARG, "pcchValue is required");
 
@@ -327,7 +327,7 @@ public: // IBundleExtensionEngine
         results.wzValue = wzValue;
         results.cchValue = *pcchValue;
 
-        hr = m_pfnBundleExtensionEngineProc(BUNDLE_EXTENSION_ENGINE_MESSAGE_GETRELATEDBUNDLEVARIABLE, &args, &results, m_pvBundleExtensionEngineProcContext);
+        hr = m_pfnBootstrapperExtensionEngineProc(BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_GETRELATEDBUNDLEVARIABLE, &args, &results, m_pvBootstrapperExtensionEngineProcContext);
 
         *pcchValue = results.cchValue;
 
@@ -336,38 +336,38 @@ public: // IBundleExtensionEngine
     }
 
 public:
-    CBextBundleExtensionEngine(
-        __in PFN_BUNDLE_EXTENSION_ENGINE_PROC pfnBundleExtensionEngineProc,
-        __in_opt LPVOID pvBundleExtensionEngineProcContext
+    CBextBootstrapperExtensionEngine(
+        __in PFN_BOOTSTRAPPER_EXTENSION_ENGINE_PROC pfnBootstrapperExtensionEngineProc,
+        __in_opt LPVOID pvBootstrapperExtensionEngineProcContext
         )
     {
         m_cReferences = 1;
-        m_pfnBundleExtensionEngineProc = pfnBundleExtensionEngineProc;
-        m_pvBundleExtensionEngineProcContext = pvBundleExtensionEngineProcContext;
+        m_pfnBootstrapperExtensionEngineProc = pfnBootstrapperExtensionEngineProc;
+        m_pvBootstrapperExtensionEngineProcContext = pvBootstrapperExtensionEngineProcContext;
     }
 
 private:
     long m_cReferences;
-    PFN_BUNDLE_EXTENSION_ENGINE_PROC m_pfnBundleExtensionEngineProc;
-    LPVOID m_pvBundleExtensionEngineProcContext;
+    PFN_BOOTSTRAPPER_EXTENSION_ENGINE_PROC m_pfnBootstrapperExtensionEngineProc;
+    LPVOID m_pvBootstrapperExtensionEngineProcContext;
 };
 
-HRESULT BextBundleExtensionEngineCreate(
-    __in PFN_BUNDLE_EXTENSION_ENGINE_PROC pfnBundleExtensionEngineProc,
-    __in_opt LPVOID pvBundleExtensionEngineProcContext,
-    __out IBundleExtensionEngine** ppEngineForExtension
+HRESULT BextBootstrapperExtensionEngineCreate(
+    __in PFN_BOOTSTRAPPER_EXTENSION_ENGINE_PROC pfnBootstrapperExtensionEngineProc,
+    __in_opt LPVOID pvBootstrapperExtensionEngineProcContext,
+    __out IBootstrapperExtensionEngine** ppEngineForExtension
     )
 {
     HRESULT hr = S_OK;
-    CBextBundleExtensionEngine* pBundleExtensionEngine = NULL;
+    CBextBootstrapperExtensionEngine* pBootstrapperExtensionEngine = NULL;
 
-    pBundleExtensionEngine = new CBextBundleExtensionEngine(pfnBundleExtensionEngineProc, pvBundleExtensionEngineProcContext);
-    ExitOnNull(pBundleExtensionEngine, hr, E_OUTOFMEMORY, "Failed to allocate new BextBundleExtensionEngine object.");
+    pBootstrapperExtensionEngine = new CBextBootstrapperExtensionEngine(pfnBootstrapperExtensionEngineProc, pvBootstrapperExtensionEngineProcContext);
+    ExitOnNull(pBootstrapperExtensionEngine, hr, E_OUTOFMEMORY, "Failed to allocate new BextBootstrapperExtensionEngine object.");
 
-    hr = pBundleExtensionEngine->QueryInterface(IID_PPV_ARGS(ppEngineForExtension));
-    ExitOnFailure(hr, "Failed to QI for IBundleExtensionEngine from BextBundleExtensionEngine object.");
+    hr = pBootstrapperExtensionEngine->QueryInterface(IID_PPV_ARGS(ppEngineForExtension));
+    ExitOnFailure(hr, "Failed to QI for IBootstrapperExtensionEngine from BextBootstrapperExtensionEngine object.");
 
 LExit:
-    ReleaseObject(pBundleExtensionEngine);
+    ReleaseObject(pBootstrapperExtensionEngine);
     return hr;
 }
diff --git a/src/api/burn/bextutil/bextutil.cpp b/src/api/burn/bextutil/bextutil.cpp
index b2e689c3..6f960ef5 100644
--- a/src/api/burn/bextutil/bextutil.cpp
+++ b/src/api/burn/bextutil/bextutil.cpp
@@ -2,12 +2,12 @@
 
 #include "precomp.h"
 
-static IBundleExtensionEngine* vpEngine = NULL;
+static IBootstrapperExtensionEngine* vpEngine = NULL;
 
 // prototypes
 
 DAPI_(void) BextInitialize(
-    __in IBundleExtensionEngine* pEngine
+    __in IBootstrapperExtensionEngine* pEngine
     )
 {
     pEngine->AddRef();
@@ -17,15 +17,15 @@ DAPI_(void) BextInitialize(
 }
 
 DAPI_(HRESULT) BextInitializeFromCreateArgs(
-    __in const BUNDLE_EXTENSION_CREATE_ARGS* pArgs,
-    __out_opt IBundleExtensionEngine** ppEngine
+    __in const BOOTSTRAPPER_EXTENSION_CREATE_ARGS* pArgs,
+    __out_opt IBootstrapperExtensionEngine** ppEngine
     )
 {
     HRESULT hr = S_OK;
-    IBundleExtensionEngine* pEngine = NULL;
+    IBootstrapperExtensionEngine* pEngine = NULL;
 
-    hr = BextBundleExtensionEngineCreate(pArgs->pfnBundleExtensionEngineProc, pArgs->pvBundleExtensionEngineProcContext, &pEngine);
-    ExitOnFailure(hr, "Failed to create BextBundleExtensionEngine.");
+    hr = BextBootstrapperExtensionEngineCreate(pArgs->pfnBootstrapperExtensionEngineProc, pArgs->pvBootstrapperExtensionEngineProcContext, &pEngine);
+    ExitOnFailure(hr, "Failed to create BextBootstrapperExtensionEngine.");
 
     BextInitialize(pEngine);
 
@@ -47,30 +47,30 @@ DAPI_(void) BextUninitialize()
     ReleaseNullObject(vpEngine);
 }
 
-DAPI_(HRESULT) BextGetBundleExtensionDataNode(
+DAPI_(HRESULT) BextGetBootstrapperExtensionDataNode(
     __in IXMLDOMDocument* pixdManifest,
     __in LPCWSTR wzExtensionId,
-    __out IXMLDOMNode** ppixnBundleExtension
+    __out IXMLDOMNode** ppixnBootstrapperExtension
     )
 {
     HRESULT hr = S_OK;
-    IXMLDOMElement* pixeBundleExtensionData = NULL;
+    IXMLDOMElement* pixeBootstrapperExtensionData = NULL;
     IXMLDOMNodeList* pixnNodes = NULL;
     IXMLDOMNode* pixnNode = NULL;
     DWORD cNodes = 0;
     LPWSTR sczId = NULL;
 
-    // Get BundleExtensionData element.
-    hr = pixdManifest->get_documentElement(&pixeBundleExtensionData);
-    ExitOnFailure(hr, "Failed to get BundleExtensionData element.");
+    // Get BootstrapperExtensionData element.
+    hr = pixdManifest->get_documentElement(&pixeBootstrapperExtensionData);
+    ExitOnFailure(hr, "Failed to get BootstrapperExtensionData element.");
 
-    // Select BundleExtension nodes.
-    hr = XmlSelectNodes(pixeBundleExtensionData, L"BundleExtension", &pixnNodes);
-    ExitOnFailure(hr, "Failed to select BundleExtension nodes.");
+    // Select BootstrapperExtension nodes.
+    hr = XmlSelectNodes(pixeBootstrapperExtensionData, L"BootstrapperExtension", &pixnNodes);
+    ExitOnFailure(hr, "Failed to select BootstrapperExtension nodes.");
 
-    // Get BundleExtension node count.
+    // Get BootstrapperExtension node count.
     hr = pixnNodes->get_length((long*)&cNodes);
-    ExitOnFailure(hr, "Failed to get BundleExtension node count.");
+    ExitOnFailure(hr, "Failed to get BootstrapperExtension node count.");
 
     if (!cNodes)
     {
@@ -89,7 +89,7 @@ DAPI_(HRESULT) BextGetBundleExtensionDataNode(
 
         if (CSTR_EQUAL == ::CompareStringW(LOCALE_INVARIANT, 0, sczId, -1, wzExtensionId, -1))
         {
-            *ppixnBundleExtension = pixnNode;
+            *ppixnBootstrapperExtension = pixnNode;
             pixnNode = NULL;
 
             ExitFunction1(hr = S_OK);
@@ -105,14 +105,14 @@ LExit:
     ReleaseStr(sczId);
     ReleaseObject(pixnNode);
     ReleaseObject(pixnNodes);
-    ReleaseObject(pixeBundleExtensionData);
+    ReleaseObject(pixeBootstrapperExtensionData);
 
     return hr;
 }
 
 
 DAPIV_(HRESULT) BextLog(
-    __in BUNDLE_EXTENSION_LOG_LEVEL level,
+    __in BOOTSTRAPPER_EXTENSION_LOG_LEVEL level,
     __in_z __format_string LPCSTR szFormat,
     ...
     )
@@ -136,7 +136,7 @@ LExit:
 
 
 DAPI_(HRESULT) BextLogArgs(
-    __in BUNDLE_EXTENSION_LOG_LEVEL level,
+    __in BOOTSTRAPPER_EXTENSION_LOG_LEVEL level,
     __in_z __format_string LPCSTR szFormat,
     __in va_list args
     )
@@ -212,7 +212,7 @@ DAPI_(HRESULT) BextLogErrorArgs(
     hr = StrAllocFormatted(&sczMessage, L"Error 0x%08x: %S", hrError, sczFormattedAnsi);
     ExitOnFailure(hr, "Failed to prepend error number to error log string.");
 
-    hr = vpEngine->Log(BUNDLE_EXTENSION_LOG_LEVEL_ERROR, sczMessage);
+    hr = vpEngine->Log(BOOTSTRAPPER_EXTENSION_LOG_LEVEL_ERROR, sczMessage);
 
 LExit:
     ReleaseStr(sczMessage);
diff --git a/src/api/burn/bextutil/bextutil.nuspec b/src/api/burn/bextutil/bextutil.nuspec
index b2881354..c710f424 100644
--- a/src/api/burn/bextutil/bextutil.nuspec
+++ b/src/api/burn/bextutil/bextutil.nuspec
@@ -21,8 +21,8 @@
     <file src="$projectFolder$\build\$id$.props" target="build\" />
     <file src="$projectFolder$\..\..\..\internal\images\wix.png" />
     <file src="$projectFolder$\inc\*" target="build\native\include" />
-    <file src="$projectFolder$\..\inc\BundleExtension.h" target="build\native\include" />
-    <file src="$projectFolder$\..\inc\BundleExtensionEngine.h" target="build\native\include" />
+    <file src="$projectFolder$\..\inc\BootstrapperExtension.h" target="build\native\include" />
+    <file src="$projectFolder$\..\inc\BootstrapperExtensionEngine.h" target="build\native\include" />
     <file src="..\..\v141\x86\bextutil.lib" target="build\native\v14\x86" />
     <file src="..\..\v141\x64\bextutil.lib" target="build\native\v14\x64" />
     <file src="..\..\v141\ARM64\bextutil.lib" target="build\native\v14\ARM64" />
diff --git a/src/api/burn/bextutil/bextutil.vcxproj b/src/api/burn/bextutil/bextutil.vcxproj
index 467f2d56..0299c381 100644
--- a/src/api/burn/bextutil/bextutil.vcxproj
+++ b/src/api/burn/bextutil/bextutil.vcxproj
@@ -34,8 +34,8 @@
     <ConfigurationType>StaticLibrary</ConfigurationType>
     <TargetName>bextutil</TargetName>
     <CharacterSet>MultiByte</CharacterSet>
-    <Description>WiX Toolset Bundle Extension native utility library</Description>
-    <PackageId>WixToolset.BextUtil</PackageId>
+    <Description>WiX Toolset Bundle Extension API</Description>
+    <PackageId>WixToolset.BootstrapperExtensionApi</PackageId>
   </PropertyGroup>
 
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
@@ -53,19 +53,19 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <ClCompile Include="BextBundleExtensionEngine.cpp" />
+    <ClCompile Include="BextBootstrapperExtensionEngine.cpp" />
     <ClCompile Include="bextutil.cpp" />
     <ClCompile Include="precomp.cpp">
       <PrecompiledHeader>Create</PrecompiledHeader>
     </ClCompile>
   </ItemGroup>
   <ItemGroup>
-    <ClInclude Include="inc\BextBaseBundleExtension.h" />
-    <ClInclude Include="inc\BextBaseBundleExtensionProc.h" />
-    <ClInclude Include="inc\BextBundleExtensionEngine.h" />
+    <ClInclude Include="inc\BextBaseBootstrapperExtension.h" />
+    <ClInclude Include="inc\BextBaseBootstrapperExtensionProc.h" />
+    <ClInclude Include="inc\BextBootstrapperExtensionEngine.h" />
     <ClInclude Include="inc\bextutil.h" />
-    <ClInclude Include="inc\IBundleExtension.h" />
-    <ClInclude Include="inc\IBundleExtensionEngine.h" />
+    <ClInclude Include="inc\IBootstrapperExtension.h" />
+    <ClInclude Include="inc\IBootstrapperExtensionEngine.h" />
     <ClInclude Include="precomp.h" />
   </ItemGroup>
 
diff --git a/src/api/burn/bextutil/build/WixToolset.BextUtil.props b/src/api/burn/bextutil/build/WixToolset.BootstrapperExtensionApi.props
index dbaddb70..dbaddb70 100644
--- a/src/api/burn/bextutil/build/WixToolset.BextUtil.props
+++ b/src/api/burn/bextutil/build/WixToolset.BootstrapperExtensionApi.props
diff --git a/src/api/burn/bextutil/inc/BextBaseBundleExtension.h b/src/api/burn/bextutil/inc/BextBaseBootstrapperExtension.h
index 5bda04e1..83ba23a6 100644
--- a/src/api/burn/bextutil/inc/BextBaseBundleExtension.h
+++ b/src/api/burn/bextutil/inc/BextBaseBootstrapperExtension.h
@@ -4,7 +4,7 @@
 
 #include "bextutil.h"
 
-class CBextBaseBundleExtension : public IBundleExtension
+class CBextBaseBootstrapperExtension : public IBootstrapperExtension
 {
 public: // IUnknown
     virtual STDMETHODIMP QueryInterface(
@@ -19,9 +19,9 @@ public: // IUnknown
 
         *ppvObject = NULL;
 
-        if (::IsEqualIID(__uuidof(IBundleExtension), riid))
+        if (::IsEqualIID(__uuidof(IBootstrapperExtension), riid))
         {
-            *ppvObject = static_cast<IBundleExtension*>(this);
+            *ppvObject = static_cast<IBootstrapperExtension*>(this);
         }
         else if (::IsEqualIID(IID_IUnknown, riid))
         {
@@ -53,7 +53,7 @@ public: // IUnknown
         return 0;
     }
 
-public: // IBundleExtension
+public: // IBootstrapperExtension
     virtual STDMETHODIMP Search(
         __in LPCWSTR /*wzId*/,
         __in LPCWSTR /*wzVariable*/
@@ -62,8 +62,8 @@ public: // IBundleExtension
         return E_NOTIMPL;
     }
 
-    virtual STDMETHODIMP BundleExtensionProc(
-        __in BUNDLE_EXTENSION_MESSAGE /*message*/,
+    virtual STDMETHODIMP BootstrapperExtensionProc(
+        __in BOOTSTRAPPER_EXTENSION_MESSAGE /*message*/,
         __in const LPVOID /*pvArgs*/,
         __inout LPVOID /*pvResults*/,
         __in_opt LPVOID /*pvContext*/
@@ -72,15 +72,15 @@ public: // IBundleExtension
         return E_NOTIMPL;
     }
 
-public: //CBextBaseBundleExtension
+public: //CBextBaseBootstrapperExtension
     virtual STDMETHODIMP Initialize(
-        __in const BUNDLE_EXTENSION_CREATE_ARGS* pCreateArgs
+        __in const BOOTSTRAPPER_EXTENSION_CREATE_ARGS* pCreateArgs
         )
     {
         HRESULT hr = S_OK;
 
-        hr = StrAllocString(&m_sczBundleExtensionDataPath, pCreateArgs->wzBundleExtensionDataPath, 0);
-        ExitOnFailure(hr, "Failed to copy BundleExtensionDataPath.");
+        hr = StrAllocString(&m_sczBootstrapperExtensionDataPath, pCreateArgs->wzBootstrapperExtensionDataPath, 0);
+        ExitOnFailure(hr, "Failed to copy BootstrapperExtensionDataPath.");
 
     LExit:
         return hr;
@@ -88,8 +88,8 @@ public: //CBextBaseBundleExtension
 
 protected:
 
-    CBextBaseBundleExtension(
-        __in IBundleExtensionEngine* pEngine
+    CBextBaseBootstrapperExtension(
+        __in IBootstrapperExtensionEngine* pEngine
         )
     {
         m_cReferences = 1;
@@ -97,18 +97,18 @@ protected:
         pEngine->AddRef();
         m_pEngine = pEngine;
 
-        m_sczBundleExtensionDataPath = NULL;
+        m_sczBootstrapperExtensionDataPath = NULL;
     }
 
-    virtual ~CBextBaseBundleExtension()
+    virtual ~CBextBaseBootstrapperExtension()
     {
         ReleaseNullObject(m_pEngine);
-        ReleaseStr(m_sczBundleExtensionDataPath);
+        ReleaseStr(m_sczBootstrapperExtensionDataPath);
     }
 
 protected:
-    IBundleExtensionEngine* m_pEngine;
-    LPWSTR m_sczBundleExtensionDataPath;
+    IBootstrapperExtensionEngine* m_pEngine;
+    LPWSTR m_sczBootstrapperExtensionDataPath;
 
 private:
     long m_cReferences;
diff --git a/src/api/burn/bextutil/inc/BextBaseBootstrapperExtensionProc.h b/src/api/burn/bextutil/inc/BextBaseBootstrapperExtensionProc.h
new file mode 100644
index 00000000..4f96399c
--- /dev/null
+++ b/src/api/burn/bextutil/inc/BextBaseBootstrapperExtensionProc.h
@@ -0,0 +1,46 @@
+#pragma once
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+
+#include <windows.h>
+
+#include <IBootstrapperExtensionEngine.h>
+#include <IBootstrapperExtension.h>
+
+static HRESULT BextBaseBEProcSearch(
+    __in IBootstrapperExtension* pBE,
+    __in BOOTSTRAPPER_EXTENSION_SEARCH_ARGS* pArgs,
+    __inout BOOTSTRAPPER_EXTENSION_SEARCH_RESULTS* /*pResults*/
+    )
+{
+    return pBE->Search(pArgs->wzId, pArgs->wzVariable);
+}
+
+/*******************************************************************
+BextBaseBootstrapperExtensionProc - requires pvContext to be of type IBootstrapperExtension.
+                              Provides a default mapping between the message based
+                              BootstrapperExtension interface and the COM-based BootstrapperExtension interface.
+
+*******************************************************************/
+static HRESULT WINAPI BextBaseBootstrapperExtensionProc(
+    __in BOOTSTRAPPER_EXTENSION_MESSAGE message,
+    __in const LPVOID pvArgs,
+    __inout LPVOID pvResults,
+    __in_opt LPVOID pvContext
+    )
+{
+    IBootstrapperExtension* pBE = reinterpret_cast<IBootstrapperExtension*>(pvContext);
+    HRESULT hr = pBE->BootstrapperExtensionProc(message, pvArgs, pvResults, pvContext);
+
+    if (E_NOTIMPL == hr)
+    {
+        switch (message)
+        {
+        case BOOTSTRAPPER_EXTENSION_MESSAGE_SEARCH:
+            hr = BextBaseBEProcSearch(pBE, reinterpret_cast<BOOTSTRAPPER_EXTENSION_SEARCH_ARGS*>(pvArgs), reinterpret_cast<BOOTSTRAPPER_EXTENSION_SEARCH_RESULTS*>(pvResults));
+            break;
+        }
+    }
+
+    return hr;
+}
diff --git a/src/api/burn/bextutil/inc/BextBaseBundleExtensionProc.h b/src/api/burn/bextutil/inc/BextBaseBundleExtensionProc.h
deleted file mode 100644
index cd7e3cb3..00000000
--- a/src/api/burn/bextutil/inc/BextBaseBundleExtensionProc.h
+++ /dev/null
@@ -1,46 +0,0 @@
-#pragma once
-// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
-
-
-#include <windows.h>
-
-#include <IBundleExtensionEngine.h>
-#include <IBundleExtension.h>
-
-static HRESULT BextBaseBEProcSearch(
-    __in IBundleExtension* pBE,
-    __in BUNDLE_EXTENSION_SEARCH_ARGS* pArgs,
-    __inout BUNDLE_EXTENSION_SEARCH_RESULTS* /*pResults*/
-    )
-{
-    return pBE->Search(pArgs->wzId, pArgs->wzVariable);
-}
-
-/*******************************************************************
-BextBaseBundleExtensionProc - requires pvContext to be of type IBundleExtension.
-                              Provides a default mapping between the message based
-                              BundleExtension interface and the COM-based BundleExtension interface.
-
-*******************************************************************/
-static HRESULT WINAPI BextBaseBundleExtensionProc(
-    __in BUNDLE_EXTENSION_MESSAGE message,
-    __in const LPVOID pvArgs,
-    __inout LPVOID pvResults,
-    __in_opt LPVOID pvContext
-    )
-{
-    IBundleExtension* pBE = reinterpret_cast<IBundleExtension*>(pvContext);
-    HRESULT hr = pBE->BundleExtensionProc(message, pvArgs, pvResults, pvContext);
-
-    if (E_NOTIMPL == hr)
-    {
-        switch (message)
-        {
-        case BUNDLE_EXTENSION_MESSAGE_SEARCH:
-            hr = BextBaseBEProcSearch(pBE, reinterpret_cast<BUNDLE_EXTENSION_SEARCH_ARGS*>(pvArgs), reinterpret_cast<BUNDLE_EXTENSION_SEARCH_RESULTS*>(pvResults));
-            break;
-        }
-    }
-
-    return hr;
-}
diff --git a/src/api/burn/bextutil/inc/BextBundleExtensionEngine.h b/src/api/burn/bextutil/inc/BextBootstrapperExtensionEngine.h
index 97b02f36..a27ff186 100644
--- a/src/api/burn/bextutil/inc/BextBundleExtensionEngine.h
+++ b/src/api/burn/bextutil/inc/BextBootstrapperExtensionEngine.h
@@ -1,7 +1,7 @@
 #pragma once
 // Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
 
-#include <IBundleExtensionEngine.h>
+#include <IBootstrapperExtensionEngine.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -9,10 +9,10 @@ extern "C" {
 
 // function declarations
 
-HRESULT BextBundleExtensionEngineCreate(
-    __in PFN_BUNDLE_EXTENSION_ENGINE_PROC pfnBundleExtensionEngineProc,
-    __in_opt LPVOID pvBundleExtensionEngineProcContext,
-    __out IBundleExtensionEngine** ppEngineForExtension
+HRESULT BextBootstrapperExtensionEngineCreate(
+    __in PFN_BOOTSTRAPPER_EXTENSION_ENGINE_PROC pfnBootstrapperExtensionEngineProc,
+    __in_opt LPVOID pvBootstrapperExtensionEngineProcContext,
+    __out IBootstrapperExtensionEngine** ppEngineForExtension
     );
 
 #ifdef __cplusplus
diff --git a/src/api/burn/bextutil/inc/IBootstrapperExtension.h b/src/api/burn/bextutil/inc/IBootstrapperExtension.h
new file mode 100644
index 00000000..4005a9fd
--- /dev/null
+++ b/src/api/burn/bextutil/inc/IBootstrapperExtension.h
@@ -0,0 +1,21 @@
+#pragma once
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+#include <BootstrapperExtension.h>
+
+DECLARE_INTERFACE_IID_(IBootstrapperExtension, IUnknown, "93123C9D-796B-4FCD-A507-6EDEF9A925FD")
+{
+    STDMETHOD(Search)(
+        __in LPCWSTR wzId,
+        __in LPCWSTR wzVariable
+        ) = 0;
+
+    // BootstrapperExtensionProc - The PFN_BOOTSTRAPPER_EXTENSION_PROC can call this method to give the BootstrapperExtension raw access to the callback from the engine.
+    //                       This might be used to help the BootstrapperExtension support more than one version of the engine.
+    STDMETHOD(BootstrapperExtensionProc)(
+        __in BOOTSTRAPPER_EXTENSION_MESSAGE message,
+        __in const LPVOID pvArgs,
+        __inout LPVOID pvResults,
+        __in_opt LPVOID pvContext
+        ) = 0;
+};
diff --git a/src/api/burn/bextutil/inc/IBundleExtensionEngine.h b/src/api/burn/bextutil/inc/IBootstrapperExtensionEngine.h
index a4a27fb1..b23a57b7 100644
--- a/src/api/burn/bextutil/inc/IBundleExtensionEngine.h
+++ b/src/api/burn/bextutil/inc/IBootstrapperExtensionEngine.h
@@ -1,9 +1,9 @@
 #pragma once
 // Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
 
-#include <BundleExtensionEngine.h>
+#include <BootstrapperExtensionEngine.h>
 
-DECLARE_INTERFACE_IID_(IBundleExtensionEngine, IUnknown, "9D027A39-F6B6-42CC-9737-C185089EB263")
+DECLARE_INTERFACE_IID_(IBootstrapperExtensionEngine, IUnknown, "9D027A39-F6B6-42CC-9737-C185089EB263")
 {
     STDMETHOD(EscapeString)(
         __in_z LPCWSTR wzIn,
@@ -40,7 +40,7 @@ DECLARE_INTERFACE_IID_(IBundleExtensionEngine, IUnknown, "9D027A39-F6B6-42CC-973
         ) = 0;
 
     STDMETHOD(Log)(
-        __in BUNDLE_EXTENSION_LOG_LEVEL level,
+        __in BOOTSTRAPPER_EXTENSION_LOG_LEVEL level,
         __in_z LPCWSTR wzMessage
         ) = 0;
 
diff --git a/src/api/burn/bextutil/inc/IBundleExtension.h b/src/api/burn/bextutil/inc/IBundleExtension.h
deleted file mode 100644
index 00301672..00000000
--- a/src/api/burn/bextutil/inc/IBundleExtension.h
+++ /dev/null
@@ -1,21 +0,0 @@
-#pragma once
-// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
-
-#include <BundleExtension.h>
-
-DECLARE_INTERFACE_IID_(IBundleExtension, IUnknown, "93123C9D-796B-4FCD-A507-6EDEF9A925FD")
-{
-    STDMETHOD(Search)(
-        __in LPCWSTR wzId,
-        __in LPCWSTR wzVariable
-        ) = 0;
-
-    // BundleExtensionProc - The PFN_BUNDLE_EXTENSION_PROC can call this method to give the BundleExtension raw access to the callback from the engine.
-    //                       This might be used to help the BundleExtension support more than one version of the engine.
-    STDMETHOD(BundleExtensionProc)(
-        __in BUNDLE_EXTENSION_MESSAGE message,
-        __in const LPVOID pvArgs,
-        __inout LPVOID pvResults,
-        __in_opt LPVOID pvContext
-        ) = 0;
-};
diff --git a/src/api/burn/bextutil/inc/bextutil.h b/src/api/burn/bextutil/inc/bextutil.h
index b8536444..64633cf1 100644
--- a/src/api/burn/bextutil/inc/bextutil.h
+++ b/src/api/burn/bextutil/inc/bextutil.h
@@ -4,8 +4,8 @@
 
 #include "dutil.h"
 
-#include "IBundleExtensionEngine.h"
-#include "IBundleExtension.h"
+#include "IBootstrapperExtensionEngine.h"
+#include "IBootstrapperExtension.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -33,7 +33,7 @@ extern "C" {
 #define BextExitOnOptionalXmlQueryFailure(x, b, f, ...) BextExitOnOptionalXmlQueryFailureSource(DUTIL_SOURCE_DEFAULT, x, b, f, __VA_ARGS__)
 #define BextExitOnRequiredXmlQueryFailure(x, f, ...) BextExitOnRequiredXmlQueryFailureSource(DUTIL_SOURCE_DEFAULT, x, f, __VA_ARGS__)
 
-const LPCWSTR BUNDLE_EXTENSION_MANIFEST_FILENAME = L"BundleExtensionData.xml";
+const LPCWSTR BOOTSTRAPPER_EXTENSION_MANIFEST_FILENAME = L"BootstrapperExtensionData.xml";
 
 
 /*******************************************************************
@@ -42,17 +42,17 @@ const LPCWSTR BUNDLE_EXTENSION_MANIFEST_FILENAME = L"BundleExtensionData.xml";
 
 ********************************************************************/
 DAPI_(void) BextInitialize(
-    __in IBundleExtensionEngine* pEngine
+    __in IBootstrapperExtensionEngine* pEngine
     );
 
 /*******************************************************************
- BextInitializeFromCreateArgs - convenience function to call BextBundleExtensionEngineCreate
+ BextInitializeFromCreateArgs - convenience function to call BextBootstrapperExtensionEngineCreate
                                 then pass it along to BextInitialize.
 
 ********************************************************************/
 DAPI_(HRESULT) BextInitializeFromCreateArgs(
-    __in const BUNDLE_EXTENSION_CREATE_ARGS* pArgs,
-    __out IBundleExtensionEngine** ppEngine
+    __in const BOOTSTRAPPER_EXTENSION_CREATE_ARGS* pArgs,
+    __out IBootstrapperExtensionEngine** ppEngine
     );
 
 /*******************************************************************
@@ -62,13 +62,13 @@ DAPI_(HRESULT) BextInitializeFromCreateArgs(
 DAPI_(void) BextUninitialize();
 
 /*******************************************************************
- BextGetBundleExtensionDataNode - gets the requested BundleExtension node.
+ BextGetBootstrapperExtensionDataNode - gets the requested BootstrapperExtension node.
 
 ********************************************************************/
-DAPI_(HRESULT) BextGetBundleExtensionDataNode(
+DAPI_(HRESULT) BextGetBootstrapperExtensionDataNode(
     __in IXMLDOMDocument* pixdManifest,
     __in LPCWSTR wzExtensionId,
-    __out IXMLDOMNode** ppixnBundleExtension
+    __out IXMLDOMNode** ppixnBootstrapperExtension
     );
 
 /*******************************************************************
@@ -76,7 +76,7 @@ DAPI_(HRESULT) BextGetBundleExtensionDataNode(
 
 ********************************************************************/
 DAPIV_(HRESULT) BextLog(
-    __in BUNDLE_EXTENSION_LOG_LEVEL level,
+    __in BOOTSTRAPPER_EXTENSION_LOG_LEVEL level,
     __in_z __format_string LPCSTR szFormat,
     ...
     );
@@ -86,7 +86,7 @@ DAPIV_(HRESULT) BextLog(
 
 ********************************************************************/
 DAPI_(HRESULT) BextLogArgs(
-    __in BUNDLE_EXTENSION_LOG_LEVEL level,
+    __in BOOTSTRAPPER_EXTENSION_LOG_LEVEL level,
     __in_z __format_string LPCSTR szFormat,
     __in va_list args
     );
diff --git a/src/api/burn/bextutil/precomp.h b/src/api/burn/bextutil/precomp.h
index d5714cc2..52962c06 100644
--- a/src/api/burn/bextutil/precomp.h
+++ b/src/api/burn/bextutil/precomp.h
@@ -13,4 +13,4 @@
 #include <xmlutil.h>
 
 #include "bextutil.h"
-#include "BextBundleExtensionEngine.h"
+#include "BextBootstrapperExtensionEngine.h"
diff --git a/src/api/burn/inc/BootstrapperExtension.h b/src/api/burn/inc/BootstrapperExtension.h
new file mode 100644
index 00000000..b1fa6408
--- /dev/null
+++ b/src/api/burn/inc/BootstrapperExtension.h
@@ -0,0 +1,61 @@
+#pragma once
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+#include <BootstrapperExtensionEngine.h>
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+enum BOOTSTRAPPER_EXTENSION_MESSAGE
+{
+    BOOTSTRAPPER_EXTENSION_MESSAGE_SEARCH,
+};
+
+typedef struct _BOOTSTRAPPER_EXTENSION_SEARCH_ARGS
+{
+    DWORD cbSize;
+    LPCWSTR wzId;
+    LPCWSTR wzVariable;
+} BOOTSTRAPPER_EXTENSION_SEARCH_ARGS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_SEARCH_RESULTS
+{
+    DWORD cbSize;
+} BOOTSTRAPPER_EXTENSION_SEARCH_RESULTS;
+
+extern "C" typedef HRESULT(WINAPI *PFN_BOOTSTRAPPER_EXTENSION_PROC)(
+    __in BOOTSTRAPPER_EXTENSION_MESSAGE message,
+    __in const LPVOID pvArgs,
+    __inout LPVOID pvResults,
+    __in_opt LPVOID pvContext
+    );
+
+typedef struct _BOOTSTRAPPER_EXTENSION_CREATE_ARGS
+{
+    DWORD cbSize;
+    DWORD64 qwEngineAPIVersion;
+    PFN_BOOTSTRAPPER_EXTENSION_ENGINE_PROC pfnBootstrapperExtensionEngineProc;
+    LPVOID pvBootstrapperExtensionEngineProcContext;
+    LPCWSTR wzBootstrapperWorkingFolder;
+    LPCWSTR wzBootstrapperExtensionDataPath;
+    LPCWSTR wzExtensionId;
+} BOOTSTRAPPER_EXTENSION_CREATE_ARGS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_CREATE_RESULTS
+{
+    DWORD cbSize;
+    PFN_BOOTSTRAPPER_EXTENSION_PROC pfnBootstrapperExtensionProc;
+    LPVOID pvBootstrapperExtensionProcContext;
+} BOOTSTRAPPER_EXTENSION_CREATE_RESULTS;
+
+extern "C" typedef HRESULT(WINAPI *PFN_BOOTSTRAPPER_EXTENSION_CREATE)(
+    __in const BOOTSTRAPPER_EXTENSION_CREATE_ARGS* pArgs,
+    __inout BOOTSTRAPPER_EXTENSION_CREATE_RESULTS* pResults
+    );
+
+extern "C" typedef void (WINAPI *PFN_BOOTSTRAPPER_EXTENSION_DESTROY)();
+
+#if defined(__cplusplus)
+}
+#endif
diff --git a/src/api/burn/inc/BootstrapperExtensionEngine.h b/src/api/burn/inc/BootstrapperExtensionEngine.h
new file mode 100644
index 00000000..24c304c6
--- /dev/null
+++ b/src/api/burn/inc/BootstrapperExtensionEngine.h
@@ -0,0 +1,200 @@
+#pragma once
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+enum BOOTSTRAPPER_EXTENSION_LOG_LEVEL
+{
+    BOOTSTRAPPER_EXTENSION_LOG_LEVEL_NONE,      // turns off report (only valid for XXXSetLevel())
+    BOOTSTRAPPER_EXTENSION_LOG_LEVEL_STANDARD,  // written if reporting is on
+    BOOTSTRAPPER_EXTENSION_LOG_LEVEL_VERBOSE,   // written only if verbose reporting is on
+    BOOTSTRAPPER_EXTENSION_LOG_LEVEL_DEBUG,     // reporting useful when debugging code
+    BOOTSTRAPPER_EXTENSION_LOG_LEVEL_ERROR,     // always gets reported, but can never be specified
+};
+
+enum BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE
+{
+    BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_ESCAPESTRING,
+    BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_EVALUATECONDITION,
+    BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_FORMATSTRING,
+    BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_GETVARIABLENUMERIC,
+    BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_GETVARIABLESTRING,
+    BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_GETVARIABLEVERSION,
+    BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_LOG,
+    BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_SETVARIABLENUMERIC,
+    BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_SETVARIABLESTRING,
+    BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_SETVARIABLEVERSION,
+    BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_COMPAREVERSIONS,
+    BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_GETRELATEDBUNDLEVARIABLE,
+};
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_COMPAREVERSIONS_ARGS
+{
+    DWORD cbSize;
+    LPCWSTR wzVersion1;
+    LPCWSTR wzVersion2;
+} BOOTSTRAPPER_EXTENSION_ENGINE_COMPAREVERSIONS_ARGS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_COMPAREVERSIONS_RESULTS
+{
+    DWORD cbSize;
+    int nResult;
+} BOOTSTRAPPER_EXTENSION_ENGINE_COMPAREVERSIONS_RESULTS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_ESCAPESTRING_ARGS
+{
+    DWORD cbSize;
+    LPCWSTR wzIn;
+} BOOTSTRAPPER_EXTENSION_ENGINE_ESCAPESTRING_ARGS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_ESCAPESTRING_RESULTS
+{
+    DWORD cbSize;
+    LPWSTR wzOut;
+    // Should be initialized to the size of wzOut.
+    SIZE_T cchOut;
+} BOOTSTRAPPER_EXTENSION_ENGINE_ESCAPESTRING_RESULTS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_EVALUATECONDITION_ARGS
+{
+    DWORD cbSize;
+    LPCWSTR wzCondition;
+} BOOTSTRAPPER_EXTENSION_ENGINE_EVALUATECONDITION_ARGS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_EVALUATECONDITION_RESULTS
+{
+    DWORD cbSize;
+    BOOL f;
+} BOOTSTRAPPER_EXTENSION_ENGINE_EVALUATECONDITION_RESULTS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_FORMATSTRING_ARGS
+{
+    DWORD cbSize;
+    LPCWSTR wzIn;
+} BOOTSTRAPPER_EXTENSION_ENGINE_FORMATSTRING_ARGS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_FORMATSTRING_RESULTS
+{
+    DWORD cbSize;
+    LPWSTR wzOut;
+    // Should be initialized to the size of wzOut.
+    SIZE_T cchOut;
+} BOOTSTRAPPER_EXTENSION_ENGINE_FORMATSTRING_RESULTS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLENUMERIC_ARGS
+{
+    DWORD cbSize;
+    LPCWSTR wzVariable;
+} BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLENUMERIC_ARGS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLENUMERIC_RESULTS
+{
+    DWORD cbSize;
+    LONGLONG llValue;
+} BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLENUMERIC_RESULTS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLESTRING_ARGS
+{
+    DWORD cbSize;
+    LPCWSTR wzVariable;
+} BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLESTRING_ARGS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLESTRING_RESULTS
+{
+    DWORD cbSize;
+    LPWSTR wzValue;
+    // Should be initialized to the size of wzValue.
+    SIZE_T cchValue;
+} BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLESTRING_RESULTS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLEVERSION_ARGS
+{
+    DWORD cbSize;
+    LPCWSTR wzVariable;
+} BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLEVERSION_ARGS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLEVERSION_RESULTS
+{
+    DWORD cbSize;
+    LPWSTR wzValue;
+    // Should be initialized to the size of wzValue.
+    SIZE_T cchValue;
+} BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLEVERSION_RESULTS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_LOG_ARGS
+{
+    DWORD cbSize;
+    BOOTSTRAPPER_EXTENSION_LOG_LEVEL level;
+    LPCWSTR wzMessage;
+} BOOTSTRAPPER_EXTENSION_ENGINE_LOG_ARGS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_LOG_RESULTS
+{
+    DWORD cbSize;
+} BOOTSTRAPPER_EXTENSION_ENGINE_LOG_RESULTS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLENUMERIC_ARGS
+{
+    DWORD cbSize;
+    LPCWSTR wzVariable;
+    LONGLONG llValue;
+} BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLENUMERIC_ARGS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLENUMERIC_RESULTS
+{
+    DWORD cbSize;
+} BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLENUMERIC_RESULTS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLESTRING_ARGS
+{
+    DWORD cbSize;
+    LPCWSTR wzVariable;
+    LPCWSTR wzValue;
+    BOOL fFormatted;
+} BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLESTRING_ARGS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLESTRING_RESULTS
+{
+    DWORD cbSize;
+} BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLESTRING_RESULTS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLEVERSION_ARGS
+{
+    DWORD cbSize;
+    LPCWSTR wzVariable;
+    LPCWSTR wzValue;
+} BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLEVERSION_ARGS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLEVERSION_RESULTS
+{
+    DWORD cbSize;
+} BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLEVERSION_RESULTS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_GETRELATEDBUNDLEVARIABLE_ARGS
+{
+    DWORD cbSize;
+    LPCWSTR wzBundleId;
+    LPCWSTR wzVariable;
+} BOOTSTRAPPER_EXTENSION_ENGINE_GETRELATEDBUNDLEVARIABLE_ARGS;
+
+typedef struct _BOOTSTRAPPER_EXTENSION_ENGINE_GETRELATEDBUNDLEVARIABLE_RESULTS
+{
+    DWORD cbSize;
+    LPWSTR wzValue;
+    // Should be initialized to the size of wzValue.
+    SIZE_T cchValue;
+} BOOTSTRAPPER_EXTENSION_ENGINE_GETRELATEDBUNDLEVARIABLE_RESULTS;
+
+extern "C" typedef HRESULT(WINAPI *PFN_BOOTSTRAPPER_EXTENSION_ENGINE_PROC)(
+    __in BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE message,
+    __in const LPVOID pvArgs,
+    __inout LPVOID pvResults,
+    __in_opt LPVOID pvContext
+    );
+
+#if defined(__cplusplus)
+}
+#endif
diff --git a/src/api/burn/inc/BundleExtension.h b/src/api/burn/inc/BundleExtension.h
deleted file mode 100644
index 17acff6e..00000000
--- a/src/api/burn/inc/BundleExtension.h
+++ /dev/null
@@ -1,61 +0,0 @@
-#pragma once
-// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
-
-#include <BundleExtensionEngine.h>
-
-#if defined(__cplusplus)
-extern "C" {
-#endif
-
-enum BUNDLE_EXTENSION_MESSAGE
-{
-    BUNDLE_EXTENSION_MESSAGE_SEARCH,
-};
-
-typedef struct _BUNDLE_EXTENSION_SEARCH_ARGS
-{
-    DWORD cbSize;
-    LPCWSTR wzId;
-    LPCWSTR wzVariable;
-} BUNDLE_EXTENSION_SEARCH_ARGS;
-
-typedef struct _BUNDLE_EXTENSION_SEARCH_RESULTS
-{
-    DWORD cbSize;
-} BUNDLE_EXTENSION_SEARCH_RESULTS;
-
-extern "C" typedef HRESULT(WINAPI *PFN_BUNDLE_EXTENSION_PROC)(
-    __in BUNDLE_EXTENSION_MESSAGE message,
-    __in const LPVOID pvArgs,
-    __inout LPVOID pvResults,
-    __in_opt LPVOID pvContext
-    );
-
-typedef struct _BUNDLE_EXTENSION_CREATE_ARGS
-{
-    DWORD cbSize;
-    DWORD64 qwEngineAPIVersion;
-    PFN_BUNDLE_EXTENSION_ENGINE_PROC pfnBundleExtensionEngineProc;
-    LPVOID pvBundleExtensionEngineProcContext;
-    LPCWSTR wzBootstrapperWorkingFolder;
-    LPCWSTR wzBundleExtensionDataPath;
-    LPCWSTR wzExtensionId;
-} BUNDLE_EXTENSION_CREATE_ARGS;
-
-typedef struct _BUNDLE_EXTENSION_CREATE_RESULTS
-{
-    DWORD cbSize;
-    PFN_BUNDLE_EXTENSION_PROC pfnBundleExtensionProc;
-    LPVOID pvBundleExtensionProcContext;
-} BUNDLE_EXTENSION_CREATE_RESULTS;
-
-extern "C" typedef HRESULT(WINAPI *PFN_BUNDLE_EXTENSION_CREATE)(
-    __in const BUNDLE_EXTENSION_CREATE_ARGS* pArgs,
-    __inout BUNDLE_EXTENSION_CREATE_RESULTS* pResults
-    );
-
-extern "C" typedef void (WINAPI *PFN_BUNDLE_EXTENSION_DESTROY)();
-
-#if defined(__cplusplus)
-}
-#endif
diff --git a/src/api/burn/inc/BundleExtensionEngine.h b/src/api/burn/inc/BundleExtensionEngine.h
deleted file mode 100644
index b585d1a2..00000000
--- a/src/api/burn/inc/BundleExtensionEngine.h
+++ /dev/null
@@ -1,200 +0,0 @@
-#pragma once
-// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
-
-
-#if defined(__cplusplus)
-extern "C" {
-#endif
-
-enum BUNDLE_EXTENSION_LOG_LEVEL
-{
-    BUNDLE_EXTENSION_LOG_LEVEL_NONE,      // turns off report (only valid for XXXSetLevel())
-    BUNDLE_EXTENSION_LOG_LEVEL_STANDARD,  // written if reporting is on
-    BUNDLE_EXTENSION_LOG_LEVEL_VERBOSE,   // written only if verbose reporting is on
-    BUNDLE_EXTENSION_LOG_LEVEL_DEBUG,     // reporting useful when debugging code
-    BUNDLE_EXTENSION_LOG_LEVEL_ERROR,     // always gets reported, but can never be specified
-};
-
-enum BUNDLE_EXTENSION_ENGINE_MESSAGE
-{
-    BUNDLE_EXTENSION_ENGINE_MESSAGE_ESCAPESTRING,
-    BUNDLE_EXTENSION_ENGINE_MESSAGE_EVALUATECONDITION,
-    BUNDLE_EXTENSION_ENGINE_MESSAGE_FORMATSTRING,
-    BUNDLE_EXTENSION_ENGINE_MESSAGE_GETVARIABLENUMERIC,
-    BUNDLE_EXTENSION_ENGINE_MESSAGE_GETVARIABLESTRING,
-    BUNDLE_EXTENSION_ENGINE_MESSAGE_GETVARIABLEVERSION,
-    BUNDLE_EXTENSION_ENGINE_MESSAGE_LOG,
-    BUNDLE_EXTENSION_ENGINE_MESSAGE_SETVARIABLENUMERIC,
-    BUNDLE_EXTENSION_ENGINE_MESSAGE_SETVARIABLESTRING,
-    BUNDLE_EXTENSION_ENGINE_MESSAGE_SETVARIABLEVERSION,
-    BUNDLE_EXTENSION_ENGINE_MESSAGE_COMPAREVERSIONS,
-    BUNDLE_EXTENSION_ENGINE_MESSAGE_GETRELATEDBUNDLEVARIABLE,
-};
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_COMPAREVERSIONS_ARGS
-{
-    DWORD cbSize;
-    LPCWSTR wzVersion1;
-    LPCWSTR wzVersion2;
-} BUNDLE_EXTENSION_ENGINE_COMPAREVERSIONS_ARGS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_COMPAREVERSIONS_RESULTS
-{
-    DWORD cbSize;
-    int nResult;
-} BUNDLE_EXTENSION_ENGINE_COMPAREVERSIONS_RESULTS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_ESCAPESTRING_ARGS
-{
-    DWORD cbSize;
-    LPCWSTR wzIn;
-} BUNDLE_EXTENSION_ENGINE_ESCAPESTRING_ARGS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_ESCAPESTRING_RESULTS
-{
-    DWORD cbSize;
-    LPWSTR wzOut;
-    // Should be initialized to the size of wzOut.
-    SIZE_T cchOut;
-} BUNDLE_EXTENSION_ENGINE_ESCAPESTRING_RESULTS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_EVALUATECONDITION_ARGS
-{
-    DWORD cbSize;
-    LPCWSTR wzCondition;
-} BUNDLE_EXTENSION_ENGINE_EVALUATECONDITION_ARGS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_EVALUATECONDITION_RESULTS
-{
-    DWORD cbSize;
-    BOOL f;
-} BUNDLE_EXTENSION_ENGINE_EVALUATECONDITION_RESULTS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_FORMATSTRING_ARGS
-{
-    DWORD cbSize;
-    LPCWSTR wzIn;
-} BUNDLE_EXTENSION_ENGINE_FORMATSTRING_ARGS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_FORMATSTRING_RESULTS
-{
-    DWORD cbSize;
-    LPWSTR wzOut;
-    // Should be initialized to the size of wzOut.
-    SIZE_T cchOut;
-} BUNDLE_EXTENSION_ENGINE_FORMATSTRING_RESULTS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_GETVARIABLENUMERIC_ARGS
-{
-    DWORD cbSize;
-    LPCWSTR wzVariable;
-} BUNDLE_EXTENSION_ENGINE_GETVARIABLENUMERIC_ARGS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_GETVARIABLENUMERIC_RESULTS
-{
-    DWORD cbSize;
-    LONGLONG llValue;
-} BUNDLE_EXTENSION_ENGINE_GETVARIABLENUMERIC_RESULTS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_GETVARIABLESTRING_ARGS
-{
-    DWORD cbSize;
-    LPCWSTR wzVariable;
-} BUNDLE_EXTENSION_ENGINE_GETVARIABLESTRING_ARGS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_GETVARIABLESTRING_RESULTS
-{
-    DWORD cbSize;
-    LPWSTR wzValue;
-    // Should be initialized to the size of wzValue.
-    SIZE_T cchValue;
-} BUNDLE_EXTENSION_ENGINE_GETVARIABLESTRING_RESULTS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_GETVARIABLEVERSION_ARGS
-{
-    DWORD cbSize;
-    LPCWSTR wzVariable;
-} BUNDLE_EXTENSION_ENGINE_GETVARIABLEVERSION_ARGS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_GETVARIABLEVERSION_RESULTS
-{
-    DWORD cbSize;
-    LPWSTR wzValue;
-    // Should be initialized to the size of wzValue.
-    SIZE_T cchValue;
-} BUNDLE_EXTENSION_ENGINE_GETVARIABLEVERSION_RESULTS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_LOG_ARGS
-{
-    DWORD cbSize;
-    BUNDLE_EXTENSION_LOG_LEVEL level;
-    LPCWSTR wzMessage;
-} BUNDLE_EXTENSION_ENGINE_LOG_ARGS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_LOG_RESULTS
-{
-    DWORD cbSize;
-} BUNDLE_EXTENSION_ENGINE_LOG_RESULTS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_SETVARIABLENUMERIC_ARGS
-{
-    DWORD cbSize;
-    LPCWSTR wzVariable;
-    LONGLONG llValue;
-} BUNDLE_EXTENSION_ENGINE_SETVARIABLENUMERIC_ARGS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_SETVARIABLENUMERIC_RESULTS
-{
-    DWORD cbSize;
-} BUNDLE_EXTENSION_ENGINE_SETVARIABLENUMERIC_RESULTS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_SETVARIABLESTRING_ARGS
-{
-    DWORD cbSize;
-    LPCWSTR wzVariable;
-    LPCWSTR wzValue;
-    BOOL fFormatted;
-} BUNDLE_EXTENSION_ENGINE_SETVARIABLESTRING_ARGS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_SETVARIABLESTRING_RESULTS
-{
-    DWORD cbSize;
-} BUNDLE_EXTENSION_ENGINE_SETVARIABLESTRING_RESULTS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_SETVARIABLEVERSION_ARGS
-{
-    DWORD cbSize;
-    LPCWSTR wzVariable;
-    LPCWSTR wzValue;
-} BUNDLE_EXTENSION_ENGINE_SETVARIABLEVERSION_ARGS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_SETVARIABLEVERSION_RESULTS
-{
-    DWORD cbSize;
-} BUNDLE_EXTENSION_ENGINE_SETVARIABLEVERSION_RESULTS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_GETRELATEDBUNDLEVARIABLE_ARGS
-{
-    DWORD cbSize;
-    LPCWSTR wzBundleId;
-    LPCWSTR wzVariable;
-} BUNDLE_EXTENSION_ENGINE_GETRELATEDBUNDLEVARIABLE_ARGS;
-
-typedef struct _BUNDLE_EXTENSION_ENGINE_GETRELATEDBUNDLEVARIABLE_RESULTS
-{
-    DWORD cbSize;
-    LPWSTR wzValue;
-    // Should be initialized to the size of wzValue.
-    SIZE_T cchValue;
-} BUNDLE_EXTENSION_ENGINE_GETRELATEDBUNDLEVARIABLE_RESULTS;
-
-extern "C" typedef HRESULT(WINAPI *PFN_BUNDLE_EXTENSION_ENGINE_PROC)(
-    __in BUNDLE_EXTENSION_ENGINE_MESSAGE message,
-    __in const LPVOID pvArgs,
-    __inout LPVOID pvResults,
-    __in_opt LPVOID pvContext
-    );
-
-#if defined(__cplusplus)
-}
-#endif
diff --git a/src/api/burn/test/BextUtilUnitTest/BextUtilUnitTest.vcxproj b/src/api/burn/test/BextUtilUnitTest/BextUtilUnitTest.vcxproj
index 6e8dfee1..39135dcf 100644
--- a/src/api/burn/test/BextUtilUnitTest/BextUtilUnitTest.vcxproj
+++ b/src/api/burn/test/BextUtilUnitTest/BextUtilUnitTest.vcxproj
@@ -36,18 +36,18 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <ClCompile Include="BundleExtensionTests.cpp" />
+    <ClCompile Include="BootstrapperExtensionTests.cpp" />
     <ClCompile Include="precomp.cpp">
       <PrecompiledHeader>Create</PrecompiledHeader>
       <!-- Warnings from referencing netstandard dlls -->
       <DisableSpecificWarnings>4564;4691</DisableSpecificWarnings>
     </ClCompile>
-    <ClCompile Include="TestBundleExtension.cpp" />
+    <ClCompile Include="TestBootstrapperExtension.cpp" />
   </ItemGroup>
 
   <ItemGroup>
     <ClInclude Include="precomp.h" />
-    <ClInclude Include="TestBundleExtension.h" />
+    <ClInclude Include="TestBootstrapperExtension.h" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/api/burn/test/BextUtilUnitTest/BextUtilUnitTest.vcxproj.filters b/src/api/burn/test/BextUtilUnitTest/BextUtilUnitTest.vcxproj.filters
index 73f2194d..678f04f5 100644
--- a/src/api/burn/test/BextUtilUnitTest/BextUtilUnitTest.vcxproj.filters
+++ b/src/api/burn/test/BextUtilUnitTest/BextUtilUnitTest.vcxproj.filters
@@ -15,13 +15,13 @@
     </Filter>
   </ItemGroup>
   <ItemGroup>
-    <ClCompile Include="BundleExtensionTests.cpp">
+    <ClCompile Include="BootstrapperExtensionTests.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
     <ClCompile Include="precomp.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
-    <ClCompile Include="TestBundleExtension.cpp">
+    <ClCompile Include="TestBootstrapperExtension.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
   </ItemGroup>
@@ -29,8 +29,8 @@
     <ClInclude Include="precomp.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="TestBundleExtension.h">
+    <ClInclude Include="TestBootstrapperExtension.h">
       <Filter>Header Files</Filter>
     </ClInclude>
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/src/api/burn/test/BextUtilUnitTest/BundleExtensionTests.cpp b/src/api/burn/test/BextUtilUnitTest/BootstrapperExtensionTests.cpp
index 5c5c5812..c2882587 100644
--- a/src/api/burn/test/BextUtilUnitTest/BundleExtensionTests.cpp
+++ b/src/api/burn/test/BextUtilUnitTest/BootstrapperExtensionTests.cpp
@@ -9,20 +9,20 @@ using namespace WixInternal::TestSupport::XunitExtensions;
 
 namespace BextUtilTests
 {
-    public ref class BundleExtension
+    public ref class BootstrapperExtension
     {
     public:
         [Fact]
-        void CanCreateTestBundleExtension()
+        void CanCreateTestBootstrapperExtension()
         {
             HRESULT hr = S_OK;
-            BUNDLE_EXTENSION_CREATE_ARGS args = { };
-            BUNDLE_EXTENSION_CREATE_RESULTS results = { };
-            IBundleExtensionEngine* pEngine = NULL;
-            IBundleExtension* pBundleExtension = NULL;
+            BOOTSTRAPPER_EXTENSION_CREATE_ARGS args = { };
+            BOOTSTRAPPER_EXTENSION_CREATE_RESULTS results = { };
+            IBootstrapperExtensionEngine* pEngine = NULL;
+            IBootstrapperExtension* pBootstrapperExtension = NULL;
 
             args.cbSize = sizeof(args);
-            args.wzBundleExtensionDataPath = L"test.xml";
+            args.wzBootstrapperExtensionDataPath = L"test.xml";
 
             results.cbSize = sizeof(results);
 
@@ -31,13 +31,13 @@ namespace BextUtilTests
                 hr = BextInitializeFromCreateArgs(&args, &pEngine);
                 NativeAssert::Succeeded(hr, "Failed to create engine.");
 
-                hr = TestBundleExtensionCreate(pEngine, &args, &results, &pBundleExtension);
+                hr = TestBootstrapperExtensionCreate(pEngine, &args, &results, &pBootstrapperExtension);
                 NativeAssert::Succeeded(hr, "Failed to create BootstrapperApplication.");
             }
             finally
             {
                 ReleaseObject(pEngine);
-                ReleaseObject(pBundleExtension);
+                ReleaseObject(pBootstrapperExtension);
             }
         }
     };
diff --git a/src/api/burn/test/BextUtilUnitTest/TestBootstrapperExtension.cpp b/src/api/burn/test/BextUtilUnitTest/TestBootstrapperExtension.cpp
new file mode 100644
index 00000000..225123da
--- /dev/null
+++ b/src/api/burn/test/BextUtilUnitTest/TestBootstrapperExtension.cpp
@@ -0,0 +1,42 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+#include "precomp.h"
+#include "BextBaseBootstrapperExtension.h"
+#include "BextBaseBootstrapperExtensionProc.h"
+
+class CTestBootstrapperExtension : public CBextBaseBootstrapperExtension
+{
+public:
+    CTestBootstrapperExtension(
+        __in IBootstrapperExtensionEngine* pEngine
+        ) : CBextBaseBootstrapperExtension(pEngine)
+    {
+    }
+};
+
+HRESULT TestBootstrapperExtensionCreate(
+    __in IBootstrapperExtensionEngine* pEngine,
+    __in const BOOTSTRAPPER_EXTENSION_CREATE_ARGS* pArgs,
+    __inout BOOTSTRAPPER_EXTENSION_CREATE_RESULTS* pResults,
+    __out IBootstrapperExtension** ppBootstrapperExtension
+    )
+{
+    HRESULT hr = S_OK;
+    CTestBootstrapperExtension* pExtension = NULL;
+
+    pExtension = new CTestBootstrapperExtension(pEngine);
+    ExitOnNull(pExtension, hr, E_OUTOFMEMORY, "Failed to create new CTestBootstrapperExtension.");
+
+    hr = pExtension->Initialize(pArgs);
+    ExitOnFailure(hr, "CTestBootstrapperExtension initialization failed");
+
+    pResults->pfnBootstrapperExtensionProc = BextBaseBootstrapperExtensionProc;
+    pResults->pvBootstrapperExtensionProcContext = pExtension;
+
+    *ppBootstrapperExtension = pExtension;
+    pExtension = NULL;
+
+LExit:
+    ReleaseObject(pExtension);
+    return hr;
+}
diff --git a/src/api/burn/test/BextUtilUnitTest/TestBootstrapperExtension.h b/src/api/burn/test/BextUtilUnitTest/TestBootstrapperExtension.h
new file mode 100644
index 00000000..00e4243c
--- /dev/null
+++ b/src/api/burn/test/BextUtilUnitTest/TestBootstrapperExtension.h
@@ -0,0 +1,9 @@
+#pragma once
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+HRESULT TestBootstrapperExtensionCreate(
+    __in IBootstrapperExtensionEngine* pEngine,
+    __in const BOOTSTRAPPER_EXTENSION_CREATE_ARGS* pArgs,
+    __inout BOOTSTRAPPER_EXTENSION_CREATE_RESULTS* pResults,
+    __out IBootstrapperExtension** ppBootstrapperExtension
+    );
diff --git a/src/api/burn/test/BextUtilUnitTest/TestBundleExtension.cpp b/src/api/burn/test/BextUtilUnitTest/TestBundleExtension.cpp
deleted file mode 100644
index 921303bb..00000000
--- a/src/api/burn/test/BextUtilUnitTest/TestBundleExtension.cpp
+++ /dev/null
@@ -1,42 +0,0 @@
-// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
-
-#include "precomp.h"
-#include "BextBaseBundleExtension.h"
-#include "BextBaseBundleExtensionProc.h"
-
-class CTestBundleExtension : public CBextBaseBundleExtension
-{
-public:
-    CTestBundleExtension(
-        __in IBundleExtensionEngine* pEngine
-        ) : CBextBaseBundleExtension(pEngine)
-    {
-    }
-};
-
-HRESULT TestBundleExtensionCreate(
-    __in IBundleExtensionEngine* pEngine,
-    __in const BUNDLE_EXTENSION_CREATE_ARGS* pArgs,
-    __inout BUNDLE_EXTENSION_CREATE_RESULTS* pResults,
-    __out IBundleExtension** ppBundleExtension
-    )
-{
-    HRESULT hr = S_OK;
-    CTestBundleExtension* pExtension = NULL;
-
-    pExtension = new CTestBundleExtension(pEngine);
-    ExitOnNull(pExtension, hr, E_OUTOFMEMORY, "Failed to create new CTestBundleExtension.");
-
-    hr = pExtension->Initialize(pArgs);
-    ExitOnFailure(hr, "CTestBundleExtension initialization failed");
-
-    pResults->pfnBundleExtensionProc = BextBaseBundleExtensionProc;
-    pResults->pvBundleExtensionProcContext = pExtension;
-
-    *ppBundleExtension = pExtension;
-    pExtension = NULL;
-
-LExit:
-    ReleaseObject(pExtension);
-    return hr;
-}
diff --git a/src/api/burn/test/BextUtilUnitTest/TestBundleExtension.h b/src/api/burn/test/BextUtilUnitTest/TestBundleExtension.h
deleted file mode 100644
index 5cfe8b39..00000000
--- a/src/api/burn/test/BextUtilUnitTest/TestBundleExtension.h
+++ /dev/null
@@ -1,9 +0,0 @@
-#pragma once
-// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
-
-HRESULT TestBundleExtensionCreate(
-    __in IBundleExtensionEngine* pEngine,
-    __in const BUNDLE_EXTENSION_CREATE_ARGS* pArgs,
-    __inout BUNDLE_EXTENSION_CREATE_RESULTS* pResults,
-    __out IBundleExtension** ppBundleExtension
-    );
diff --git a/src/api/burn/test/BextUtilUnitTest/precomp.h b/src/api/burn/test/BextUtilUnitTest/precomp.h
index 00bf872f..893a2ac4 100644
--- a/src/api/burn/test/BextUtilUnitTest/precomp.h
+++ b/src/api/burn/test/BextUtilUnitTest/precomp.h
@@ -9,7 +9,7 @@
 #include <strutil.h>
 #include <bextutil.h>
 
-#include "TestBundleExtension.h"
+#include "TestBootstrapperExtension.h"
 
 #pragma managed
 #include <vcclr.h>
diff --git a/src/api/wix/WixToolset.Data/Burn/BurnConstants.cs b/src/api/wix/WixToolset.Data/Burn/BurnConstants.cs
index 9e74827c..1b082952 100644
--- a/src/api/wix/WixToolset.Data/Burn/BurnConstants.cs
+++ b/src/api/wix/WixToolset.Data/Burn/BurnConstants.cs
@@ -11,13 +11,13 @@ namespace WixToolset.Data.Burn
         public const string BundleLayoutOnlyPayloadsName = "BundleLayoutOnlyPayloads";
 
         public const string BurnManifestWixOutputStreamName = "wix-burndata.xml";
-        public const string BundleExtensionDataWixOutputStreamName = "wix-bextdata";
+        public const string BootstrapperExtensionDataWixOutputStreamName = "wix-bextdata";
         public const string BootstrapperApplicationDataWixOutputStreamName = "wix-badata.xml";
 
         public const string BootstrapperApplicationDataNamespace = "http://wixtoolset.org/schemas/v4/BootstrapperApplicationData";
-        public const string BundleExtensionDataNamespace = "http://wixtoolset.org/schemas/v4/BundleExtensionData";
+        public const string BootstrapperExtensionDataNamespace = "http://wixtoolset.org/schemas/v4/BootstrapperExtensionData";
 
         public const string BootstrapperApplicationDataSymbolDefinitionTag = "WixBootstrapperApplicationData";
-        public const string BundleExtensionSearchSymbolDefinitionTag = "WixBundleExtensionSearch";
+        public const string BootstrapperExtensionSearchSymbolDefinitionTag = "WixBootstrapperExtensionSearch";
     }
 }
diff --git a/src/api/wix/WixToolset.Data/Symbols/SymbolDefinitions.cs b/src/api/wix/WixToolset.Data/Symbols/SymbolDefinitions.cs
index 688c34ed..facca956 100644
--- a/src/api/wix/WixToolset.Data/Symbols/SymbolDefinitions.cs
+++ b/src/api/wix/WixToolset.Data/Symbols/SymbolDefinitions.cs
@@ -130,7 +130,7 @@ namespace WixToolset.Data
         WixBundleBundlePackagePayload,
         WixBundleExePackage,
         WixBundleExePackagePayload,
-        WixBundleExtension,
+        WixBootstrapperExtension,
         WixBundleHarvestedBundlePackage,
         WixBundleHarvestedDependencyProvider,
         WixBundleHarvestedMsiPackage,
@@ -579,8 +579,8 @@ namespace WixToolset.Data
                 case SymbolDefinitionType.WixBundleCustomDataCell:
                     return SymbolDefinitions.WixBundleCustomDataCell;
 
-                case SymbolDefinitionType.WixBundleExtension:
-                    return SymbolDefinitions.WixBundleExtension;
+                case SymbolDefinitionType.WixBootstrapperExtension:
+                    return SymbolDefinitions.WixBootstrapperExtension;
 
                 case SymbolDefinitionType.WixBundleExePackage:
                     return SymbolDefinitions.WixBundleExePackage;
diff --git a/src/api/wix/WixToolset.Data/Symbols/WixBootstrapperExtensionSymbol.cs b/src/api/wix/WixToolset.Data/Symbols/WixBootstrapperExtensionSymbol.cs
new file mode 100644
index 00000000..b53848fc
--- /dev/null
+++ b/src/api/wix/WixToolset.Data/Symbols/WixBootstrapperExtensionSymbol.cs
@@ -0,0 +1,44 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+namespace WixToolset.Data
+{
+    using WixToolset.Data.Symbols;
+
+    public static partial class SymbolDefinitions
+    {
+        public static readonly IntermediateSymbolDefinition WixBootstrapperExtension = new IntermediateSymbolDefinition(
+            SymbolDefinitionType.WixBootstrapperExtension,
+            new[]
+            {
+                new IntermediateFieldDefinition(nameof(WixBootstrapperExtensionSymbolFields.PayloadRef), IntermediateFieldType.String),
+            },
+            typeof(WixBootstrapperExtensionSymbol));
+    }
+}
+
+namespace WixToolset.Data.Symbols
+{
+    public enum WixBootstrapperExtensionSymbolFields
+    {
+        PayloadRef,
+    }
+
+    public class WixBootstrapperExtensionSymbol : IntermediateSymbol
+    {
+        public WixBootstrapperExtensionSymbol() : base(SymbolDefinitions.WixBootstrapperExtension, null, null)
+        {
+        }
+
+        public WixBootstrapperExtensionSymbol(SourceLineNumber sourceLineNumber, Identifier id = null) : base(SymbolDefinitions.WixBootstrapperExtension, sourceLineNumber, id)
+        {
+        }
+
+        public IntermediateField this[WixBootstrapperExtensionSymbolFields index] => this.Fields[(int)index];
+
+        public string PayloadRef
+        {
+            get => (string)this.Fields[(int)WixBootstrapperExtensionSymbolFields.PayloadRef];
+            set => this.Set((int)WixBootstrapperExtensionSymbolFields.PayloadRef, value);
+        }
+    }
+}
diff --git a/src/api/wix/WixToolset.Data/Symbols/WixBundleCustomDataSymbol.cs b/src/api/wix/WixToolset.Data/Symbols/WixBundleCustomDataSymbol.cs
index 0490f9f7..032ebda8 100644
--- a/src/api/wix/WixToolset.Data/Symbols/WixBundleCustomDataSymbol.cs
+++ b/src/api/wix/WixToolset.Data/Symbols/WixBundleCustomDataSymbol.cs
@@ -12,7 +12,7 @@ namespace WixToolset.Data
             {
                 new IntermediateFieldDefinition(nameof(WixBundleCustomDataSymbolFields.AttributeNames), IntermediateFieldType.String),
                 new IntermediateFieldDefinition(nameof(WixBundleCustomDataSymbolFields.Type), IntermediateFieldType.Number),
-                new IntermediateFieldDefinition(nameof(WixBundleCustomDataSymbolFields.BundleExtensionRef), IntermediateFieldType.String),
+                new IntermediateFieldDefinition(nameof(WixBundleCustomDataSymbolFields.BootstrapperExtensionRef), IntermediateFieldType.String),
             },
             typeof(WixBundleCustomDataSymbol));
     }
@@ -24,14 +24,14 @@ namespace WixToolset.Data.Symbols
     {
         AttributeNames,
         Type,
-        BundleExtensionRef,
+        BootstrapperExtensionRef,
     }
 
     public enum WixBundleCustomDataType
     {
         Unknown,
         BootstrapperApplication,
-        BundleExtension,
+        BootstrapperExtension,
     }
 
     public class WixBundleCustomDataSymbol : IntermediateSymbol
@@ -60,10 +60,10 @@ namespace WixToolset.Data.Symbols
             set => this.Set((int)WixBundleCustomDataSymbolFields.Type, (int)value);
         }
 
-        public string BundleExtensionRef
+        public string BootstrapperExtensionRef
         {
-            get => (string)this.Fields[(int)WixBundleCustomDataSymbolFields.BundleExtensionRef];
-            set => this.Set((int)WixBundleCustomDataSymbolFields.BundleExtensionRef, value);
+            get => (string)this.Fields[(int)WixBundleCustomDataSymbolFields.BootstrapperExtensionRef];
+            set => this.Set((int)WixBundleCustomDataSymbolFields.BootstrapperExtensionRef, value);
         }
 
         public string[] AttributeNamesSeparated => this.AttributeNames.Split(AttributeNamesSeparator);
diff --git a/src/api/wix/WixToolset.Data/Symbols/WixBundleExtensionSymbol.cs b/src/api/wix/WixToolset.Data/Symbols/WixBundleExtensionSymbol.cs
deleted file mode 100644
index 8e6bea58..00000000
--- a/src/api/wix/WixToolset.Data/Symbols/WixBundleExtensionSymbol.cs
+++ /dev/null
@@ -1,44 +0,0 @@
-// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
-
-namespace WixToolset.Data
-{
-    using WixToolset.Data.Symbols;
-
-    public static partial class SymbolDefinitions
-    {
-        public static readonly IntermediateSymbolDefinition WixBundleExtension = new IntermediateSymbolDefinition(
-            SymbolDefinitionType.WixBundleExtension,
-            new[]
-            {
-                new IntermediateFieldDefinition(nameof(WixBundleExtensionSymbolFields.PayloadRef), IntermediateFieldType.String),
-            },
-            typeof(WixBundleExtensionSymbol));
-    }
-}
-
-namespace WixToolset.Data.Symbols
-{
-    public enum WixBundleExtensionSymbolFields
-    {
-        PayloadRef,
-    }
-
-    public class WixBundleExtensionSymbol : IntermediateSymbol
-    {
-        public WixBundleExtensionSymbol() : base(SymbolDefinitions.WixBundleExtension, null, null)
-        {
-        }
-
-        public WixBundleExtensionSymbol(SourceLineNumber sourceLineNumber, Identifier id = null) : base(SymbolDefinitions.WixBundleExtension, sourceLineNumber, id)
-        {
-        }
-
-        public IntermediateField this[WixBundleExtensionSymbolFields index] => this.Fields[(int)index];
-
-        public string PayloadRef
-        {
-            get => (string)this.Fields[(int)WixBundleExtensionSymbolFields.PayloadRef];
-            set => this.Set((int)WixBundleExtensionSymbolFields.PayloadRef, value);
-        }
-    }
-}
diff --git a/src/api/wix/WixToolset.Data/Symbols/WixSearchSymbol.cs b/src/api/wix/WixToolset.Data/Symbols/WixSearchSymbol.cs
index 2d6a927c..5327d035 100644
--- a/src/api/wix/WixToolset.Data/Symbols/WixSearchSymbol.cs
+++ b/src/api/wix/WixToolset.Data/Symbols/WixSearchSymbol.cs
@@ -12,7 +12,7 @@ namespace WixToolset.Data
             {
                 new IntermediateFieldDefinition(nameof(WixSearchSymbolFields.Variable), IntermediateFieldType.String),
                 new IntermediateFieldDefinition(nameof(WixSearchSymbolFields.Condition), IntermediateFieldType.String),
-                new IntermediateFieldDefinition(nameof(WixSearchSymbolFields.BundleExtensionRef), IntermediateFieldType.String),
+                new IntermediateFieldDefinition(nameof(WixSearchSymbolFields.BootstrapperExtensionRef), IntermediateFieldType.String),
             },
             typeof(WixSearchSymbol));
     }
@@ -24,7 +24,7 @@ namespace WixToolset.Data.Symbols
     {
         Variable,
         Condition,
-        BundleExtensionRef,
+        BootstrapperExtensionRef,
     }
 
     public class WixSearchSymbol : IntermediateSymbol
@@ -51,10 +51,10 @@ namespace WixToolset.Data.Symbols
             set => this.Set((int)WixSearchSymbolFields.Condition, value);
         }
 
-        public string BundleExtensionRef
+        public string BootstrapperExtensionRef
         {
-            get => (string)this.Fields[(int)WixSearchSymbolFields.BundleExtensionRef];
-            set => this.Set((int)WixSearchSymbolFields.BundleExtensionRef, value);
+            get => (string)this.Fields[(int)WixSearchSymbolFields.BootstrapperExtensionRef];
+            set => this.Set((int)WixSearchSymbolFields.BootstrapperExtensionRef, value);
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/api/wix/WixToolset.Extensibility/Services/IBurnBackendHelper.cs b/src/api/wix/WixToolset.Extensibility/Services/IBurnBackendHelper.cs
index 1b6a2828..a404a778 100644
--- a/src/api/wix/WixToolset.Extensibility/Services/IBurnBackendHelper.cs
+++ b/src/api/wix/WixToolset.Extensibility/Services/IBurnBackendHelper.cs
@@ -28,14 +28,14 @@ namespace WixToolset.Extensibility.Services
         void AddBootstrapperApplicationData(IntermediateSymbol symbol, bool symbolIdIsIdAttribute = false);
 
         /// <summary>
-        /// Adds the given XML to the BundleExtensionData manifest for the given bundle extension.
+        /// Adds the given XML to the BootstrapperExtensionData manifest for the given bundle extension.
         /// </summary>
         /// <param name="extensionId">The bundle extension's id.</param>
         /// <param name="xml">A valid XML fragment.</param>
-        void AddBundleExtensionData(string extensionId, string xml);
+        void AddBootstrapperExtensionData(string extensionId, string xml);
 
         /// <summary>
-        /// Adds an XML element for the given symbol to the BundleExtensionData manifest for the given bundle extension.
+        /// Adds an XML element for the given symbol to the BootstrapperExtensionData manifest for the given bundle extension.
         /// The symbol's name is used for the element's name.
         /// All of the symbol's fields are used for the element's attributes.
         /// </summary>
@@ -45,6 +45,6 @@ namespace WixToolset.Extensibility.Services
         /// If true and the symbol has an Id,
         /// then an Id attribute is created with a value of the symbol's Id.
         /// </param>
-        void AddBundleExtensionData(string extensionId, IntermediateSymbol symbol, bool symbolIdIsIdAttribute = false);
+        void AddBootstrapperExtensionData(string extensionId, IntermediateSymbol symbol, bool symbolIdIsIdAttribute = false);
     }
 }
diff --git a/src/api/wix/WixToolset.Extensibility/Services/IParseHelper.cs b/src/api/wix/WixToolset.Extensibility/Services/IParseHelper.cs
index e7856c7c..b3b1b4c1 100644
--- a/src/api/wix/WixToolset.Extensibility/Services/IParseHelper.cs
+++ b/src/api/wix/WixToolset.Extensibility/Services/IParseHelper.cs
@@ -201,8 +201,8 @@ namespace WixToolset.Extensibility.Services
         /// <param name="variable">The Burn variable to store the result into.</param>
         /// <param name="condition">A condition to test before evaluating the search.</param>
         /// <param name="after">The search that this one will execute after.</param>
-        /// <param name="bundleExtensionId">The id of the bundle extension that handles this search.</param>
-        void CreateWixSearchSymbol(IntermediateSection section, SourceLineNumber sourceLineNumbers, string elementName, Identifier id, string variable, string condition, string after, string bundleExtensionId);
+        /// <param name="bootstrapperExtensionId">The id of the bootstrapper extension that handles this search.</param>
+        void CreateWixSearchSymbol(IntermediateSection section, SourceLineNumber sourceLineNumbers, string elementName, Identifier id, string variable, string condition, string after, string bootstrapperExtensionId);
 
         /// <summary>
         ///
diff --git a/src/burn/engine/EngineForExtension.cpp b/src/burn/engine/EngineForExtension.cpp
index bb134a61..e19cb802 100644
--- a/src/burn/engine/EngineForExtension.cpp
+++ b/src/burn/engine/EngineForExtension.cpp
@@ -10,8 +10,8 @@ static HRESULT BEEngineEscapeString(
     )
 {
     HRESULT hr = S_OK;
-    ValidateMessageArgs(hr, pvArgs, BUNDLE_EXTENSION_ENGINE_ESCAPESTRING_ARGS, pArgs);
-    ValidateMessageResults(hr, pvResults, BUNDLE_EXTENSION_ENGINE_ESCAPESTRING_RESULTS, pResults);
+    ValidateMessageArgs(hr, pvArgs, BOOTSTRAPPER_EXTENSION_ENGINE_ESCAPESTRING_ARGS, pArgs);
+    ValidateMessageResults(hr, pvResults, BOOTSTRAPPER_EXTENSION_ENGINE_ESCAPESTRING_RESULTS, pResults);
 
     hr = ExternalEngineEscapeString(pArgs->wzIn, pResults->wzOut, &pResults->cchOut);
 
@@ -26,8 +26,8 @@ static HRESULT BEEngineEvaluateCondition(
     )
 {
     HRESULT hr = S_OK;
-    ValidateMessageArgs(hr, pvArgs, BUNDLE_EXTENSION_ENGINE_EVALUATECONDITION_ARGS, pArgs);
-    ValidateMessageResults(hr, pvResults, BUNDLE_EXTENSION_ENGINE_EVALUATECONDITION_RESULTS, pResults);
+    ValidateMessageArgs(hr, pvArgs, BOOTSTRAPPER_EXTENSION_ENGINE_EVALUATECONDITION_ARGS, pArgs);
+    ValidateMessageResults(hr, pvResults, BOOTSTRAPPER_EXTENSION_ENGINE_EVALUATECONDITION_RESULTS, pResults);
 
     hr = ExternalEngineEvaluateCondition(pContext->pEngineState, pArgs->wzCondition, &pResults->f);
 
@@ -42,8 +42,8 @@ static HRESULT BEEngineFormatString(
     )
 {
     HRESULT hr = S_OK;
-    ValidateMessageArgs(hr, pvArgs, BUNDLE_EXTENSION_ENGINE_FORMATSTRING_ARGS, pArgs);
-    ValidateMessageResults(hr, pvResults, BUNDLE_EXTENSION_ENGINE_FORMATSTRING_RESULTS, pResults);
+    ValidateMessageArgs(hr, pvArgs, BOOTSTRAPPER_EXTENSION_ENGINE_FORMATSTRING_ARGS, pArgs);
+    ValidateMessageResults(hr, pvResults, BOOTSTRAPPER_EXTENSION_ENGINE_FORMATSTRING_RESULTS, pResults);
 
     hr = ExternalEngineFormatString(pContext->pEngineState, pArgs->wzIn, pResults->wzOut, &pResults->cchOut);
 
@@ -58,8 +58,8 @@ static HRESULT BEEngineGetVariableNumeric(
     )
 {
     HRESULT hr = S_OK;
-    ValidateMessageArgs(hr, pvArgs, BUNDLE_EXTENSION_ENGINE_GETVARIABLENUMERIC_ARGS, pArgs);
-    ValidateMessageResults(hr, pvResults, BUNDLE_EXTENSION_ENGINE_GETVARIABLENUMERIC_RESULTS, pResults);
+    ValidateMessageArgs(hr, pvArgs, BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLENUMERIC_ARGS, pArgs);
+    ValidateMessageResults(hr, pvResults, BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLENUMERIC_RESULTS, pResults);
 
     hr = ExternalEngineGetVariableNumeric(pContext->pEngineState, pArgs->wzVariable, &pResults->llValue);
 
@@ -74,8 +74,8 @@ static HRESULT BEEngineGetVariableString(
     )
 {
     HRESULT hr = S_OK;
-    ValidateMessageArgs(hr, pvArgs, BUNDLE_EXTENSION_ENGINE_GETVARIABLESTRING_ARGS, pArgs);
-    ValidateMessageResults(hr, pvResults, BUNDLE_EXTENSION_ENGINE_GETVARIABLESTRING_RESULTS, pResults);
+    ValidateMessageArgs(hr, pvArgs, BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLESTRING_ARGS, pArgs);
+    ValidateMessageResults(hr, pvResults, BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLESTRING_RESULTS, pResults);
 
     hr = ExternalEngineGetVariableString(pContext->pEngineState, pArgs->wzVariable, pResults->wzValue, &pResults->cchValue);
 
@@ -90,8 +90,8 @@ static HRESULT BEEngineGetVariableVersion(
     )
 {
     HRESULT hr = S_OK;
-    ValidateMessageArgs(hr, pvArgs, BUNDLE_EXTENSION_ENGINE_GETVARIABLEVERSION_ARGS, pArgs);
-    ValidateMessageResults(hr, pvResults, BUNDLE_EXTENSION_ENGINE_GETVARIABLEVERSION_RESULTS, pResults);
+    ValidateMessageArgs(hr, pvArgs, BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLEVERSION_ARGS, pArgs);
+    ValidateMessageResults(hr, pvResults, BOOTSTRAPPER_EXTENSION_ENGINE_GETVARIABLEVERSION_RESULTS, pResults);
 
     hr = ExternalEngineGetVariableVersion(pContext->pEngineState, pArgs->wzVariable, pResults->wzValue, &pResults->cchValue);
 
@@ -107,24 +107,24 @@ static HRESULT BEEngineLog(
 {
     HRESULT hr = S_OK;
     REPORT_LEVEL rl = REPORT_NONE;
-    ValidateMessageArgs(hr, pvArgs, BUNDLE_EXTENSION_ENGINE_LOG_ARGS, pArgs);
-    ValidateMessageResults(hr, pvResults, BUNDLE_EXTENSION_ENGINE_LOG_RESULTS, pResults);
+    ValidateMessageArgs(hr, pvArgs, BOOTSTRAPPER_EXTENSION_ENGINE_LOG_ARGS, pArgs);
+    ValidateMessageResults(hr, pvResults, BOOTSTRAPPER_EXTENSION_ENGINE_LOG_RESULTS, pResults);
 
     switch (pArgs->level)
     {
-    case BUNDLE_EXTENSION_LOG_LEVEL_STANDARD:
+    case BOOTSTRAPPER_EXTENSION_LOG_LEVEL_STANDARD:
         rl = REPORT_STANDARD;
         break;
 
-    case BUNDLE_EXTENSION_LOG_LEVEL_VERBOSE:
+    case BOOTSTRAPPER_EXTENSION_LOG_LEVEL_VERBOSE:
         rl = REPORT_VERBOSE;
         break;
 
-    case BUNDLE_EXTENSION_LOG_LEVEL_DEBUG:
+    case BOOTSTRAPPER_EXTENSION_LOG_LEVEL_DEBUG:
         rl = REPORT_DEBUG;
         break;
 
-    case BUNDLE_EXTENSION_LOG_LEVEL_ERROR:
+    case BOOTSTRAPPER_EXTENSION_LOG_LEVEL_ERROR:
         rl = REPORT_ERROR;
         break;
 
@@ -146,8 +146,8 @@ static HRESULT BEEngineSetVariableNumeric(
     )
 {
     HRESULT hr = S_OK;
-    ValidateMessageArgs(hr, pvArgs, BUNDLE_EXTENSION_ENGINE_SETVARIABLENUMERIC_ARGS, pArgs);
-    ValidateMessageResults(hr, pvResults, BUNDLE_EXTENSION_ENGINE_SETVARIABLENUMERIC_RESULTS, pResults);
+    ValidateMessageArgs(hr, pvArgs, BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLENUMERIC_ARGS, pArgs);
+    ValidateMessageResults(hr, pvResults, BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLENUMERIC_RESULTS, pResults);
 
     hr = ExternalEngineSetVariableNumeric(pContext->pEngineState, pArgs->wzVariable, pArgs->llValue);
 
@@ -162,8 +162,8 @@ static HRESULT BEEngineSetVariableString(
     )
 {
     HRESULT hr = S_OK;
-    ValidateMessageArgs(hr, pvArgs, BUNDLE_EXTENSION_ENGINE_SETVARIABLESTRING_ARGS, pArgs);
-    ValidateMessageResults(hr, pvResults, BUNDLE_EXTENSION_ENGINE_SETVARIABLESTRING_RESULTS, pResults);
+    ValidateMessageArgs(hr, pvArgs, BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLESTRING_ARGS, pArgs);
+    ValidateMessageResults(hr, pvResults, BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLESTRING_RESULTS, pResults);
 
     hr = ExternalEngineSetVariableString(pContext->pEngineState, pArgs->wzVariable, pArgs->wzValue, pArgs->fFormatted);
 
@@ -178,8 +178,8 @@ static HRESULT BEEngineSetVariableVersion(
     )
 {
     HRESULT hr = S_OK;
-    ValidateMessageArgs(hr, pvArgs, BUNDLE_EXTENSION_ENGINE_SETVARIABLEVERSION_ARGS, pArgs);
-    ValidateMessageResults(hr, pvResults, BUNDLE_EXTENSION_ENGINE_SETVARIABLEVERSION_RESULTS, pResults);
+    ValidateMessageArgs(hr, pvArgs, BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLEVERSION_ARGS, pArgs);
+    ValidateMessageResults(hr, pvResults, BOOTSTRAPPER_EXTENSION_ENGINE_SETVARIABLEVERSION_RESULTS, pResults);
 
     hr = ExternalEngineSetVariableVersion(pContext->pEngineState, pArgs->wzVariable, pArgs->wzValue);
 
@@ -194,8 +194,8 @@ static HRESULT BEEngineCompareVersions(
     )
 {
     HRESULT hr = S_OK;
-    ValidateMessageArgs(hr, pvArgs, BUNDLE_EXTENSION_ENGINE_COMPAREVERSIONS_ARGS, pArgs);
-    ValidateMessageResults(hr, pvResults, BUNDLE_EXTENSION_ENGINE_COMPAREVERSIONS_RESULTS, pResults);
+    ValidateMessageArgs(hr, pvArgs, BOOTSTRAPPER_EXTENSION_ENGINE_COMPAREVERSIONS_ARGS, pArgs);
+    ValidateMessageResults(hr, pvResults, BOOTSTRAPPER_EXTENSION_ENGINE_COMPAREVERSIONS_RESULTS, pResults);
 
     hr = ExternalEngineCompareVersions(pArgs->wzVersion1, pArgs->wzVersion2, &pResults->nResult);
 
@@ -210,8 +210,8 @@ static HRESULT BEEngineGetRelatedBundleVariable(
 )
 {
     HRESULT hr = S_OK;
-    ValidateMessageArgs(hr, pvArgs, BUNDLE_EXTENSION_ENGINE_GETRELATEDBUNDLEVARIABLE_ARGS, pArgs);
-    ValidateMessageResults(hr, pvResults, BUNDLE_EXTENSION_ENGINE_GETRELATEDBUNDLEVARIABLE_RESULTS, pResults);
+    ValidateMessageArgs(hr, pvArgs, BOOTSTRAPPER_EXTENSION_ENGINE_GETRELATEDBUNDLEVARIABLE_ARGS, pArgs);
+    ValidateMessageResults(hr, pvResults, BOOTSTRAPPER_EXTENSION_ENGINE_GETRELATEDBUNDLEVARIABLE_RESULTS, pResults);
 
     hr = ExternalEngineGetRelatedBundleVariable(pContext->pEngineState, pArgs->wzBundleId, pArgs->wzVariable, pResults->wzValue, &pResults->cchValue);
 
@@ -220,7 +220,7 @@ LExit:
 }
 
 HRESULT WINAPI EngineForExtensionProc(
-    __in BUNDLE_EXTENSION_ENGINE_MESSAGE message,
+    __in BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE message,
     __in const LPVOID pvArgs,
     __inout LPVOID pvResults,
     __in_opt LPVOID pvContext
@@ -236,40 +236,40 @@ HRESULT WINAPI EngineForExtensionProc(
 
     switch (message)
     {
-    case BUNDLE_EXTENSION_ENGINE_MESSAGE_ESCAPESTRING:
+    case BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_ESCAPESTRING:
         hr = BEEngineEscapeString(pContext, pvArgs, pvResults);
         break;
-    case BUNDLE_EXTENSION_ENGINE_MESSAGE_EVALUATECONDITION:
+    case BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_EVALUATECONDITION:
         hr = BEEngineEvaluateCondition(pContext, pvArgs, pvResults);
         break;
-    case BUNDLE_EXTENSION_ENGINE_MESSAGE_FORMATSTRING:
+    case BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_FORMATSTRING:
         hr = BEEngineFormatString(pContext, pvArgs, pvResults);
         break;
-    case BUNDLE_EXTENSION_ENGINE_MESSAGE_GETVARIABLENUMERIC:
+    case BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_GETVARIABLENUMERIC:
         hr = BEEngineGetVariableNumeric(pContext, pvArgs, pvResults);
         break;
-    case BUNDLE_EXTENSION_ENGINE_MESSAGE_GETVARIABLESTRING:
+    case BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_GETVARIABLESTRING:
         hr = BEEngineGetVariableString(pContext, pvArgs, pvResults);
         break;
-    case BUNDLE_EXTENSION_ENGINE_MESSAGE_GETVARIABLEVERSION:
+    case BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_GETVARIABLEVERSION:
         hr = BEEngineGetVariableVersion(pContext, pvArgs, pvResults);
         break;
-    case BUNDLE_EXTENSION_ENGINE_MESSAGE_LOG:
+    case BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_LOG:
         hr = BEEngineLog(pContext, pvArgs, pvResults);
         break;
-    case BUNDLE_EXTENSION_ENGINE_MESSAGE_SETVARIABLENUMERIC:
+    case BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_SETVARIABLENUMERIC:
         hr = BEEngineSetVariableNumeric(pContext, pvArgs, pvResults);
         break;
-    case BUNDLE_EXTENSION_ENGINE_MESSAGE_SETVARIABLESTRING:
+    case BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_SETVARIABLESTRING:
         hr = BEEngineSetVariableString(pContext, pvArgs, pvResults);
         break;
-    case BUNDLE_EXTENSION_ENGINE_MESSAGE_SETVARIABLEVERSION:
+    case BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_SETVARIABLEVERSION:
         hr = BEEngineSetVariableVersion(pContext, pvArgs, pvResults);
         break;
-    case BUNDLE_EXTENSION_ENGINE_MESSAGE_COMPAREVERSIONS:
+    case BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_COMPAREVERSIONS:
         hr = BEEngineCompareVersions(pContext, pvArgs, pvResults);
         break;
-    case BUNDLE_EXTENSION_ENGINE_MESSAGE_GETRELATEDBUNDLEVARIABLE:
+    case BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE_GETRELATEDBUNDLEVARIABLE:
         hr = BEEngineGetRelatedBundleVariable(pContext, pvArgs, pvResults);
         break;
     default:
diff --git a/src/burn/engine/EngineForExtension.h b/src/burn/engine/EngineForExtension.h
index bad5f08a..b52d4f0a 100644
--- a/src/burn/engine/EngineForExtension.h
+++ b/src/burn/engine/EngineForExtension.h
@@ -16,7 +16,7 @@ typedef struct _BURN_EXTENSION_ENGINE_CONTEXT
 // function declarations
 
 HRESULT WINAPI EngineForExtensionProc(
-    __in BUNDLE_EXTENSION_ENGINE_MESSAGE message,
+    __in BOOTSTRAPPER_EXTENSION_ENGINE_MESSAGE message,
     __in const LPVOID pvArgs,
     __inout LPVOID pvResults,
     __in_opt LPVOID pvContext
diff --git a/src/burn/engine/burnextension.cpp b/src/burn/engine/burnextension.cpp
index ee4b1542..536dbcc9 100644
--- a/src/burn/engine/burnextension.cpp
+++ b/src/burn/engine/burnextension.cpp
@@ -5,7 +5,7 @@
 
 static HRESULT SendRequiredBextMessage(
     __in BURN_EXTENSION* pExtension,
-    __in BUNDLE_EXTENSION_MESSAGE message,
+    __in BOOTSTRAPPER_EXTENSION_MESSAGE message,
     __in const LPVOID pvArgs,
     __inout LPVOID pvResults
     );
@@ -13,7 +13,7 @@ static HRESULT SendRequiredBextMessage(
 // function definitions
 
 /*******************************************************************
- BurnExtensionParseFromXml - 
+ BurnExtensionParseFromXml -
 
 *******************************************************************/
 EXTERN_C HRESULT BurnExtensionParseFromXml(
@@ -28,22 +28,22 @@ EXTERN_C HRESULT BurnExtensionParseFromXml(
     DWORD cNodes = 0;
     LPWSTR scz = NULL;
 
-    // Select BundleExtension nodes.
-    hr = XmlSelectNodes(pixnBundle, L"BundleExtension", &pixnNodes);
-    ExitOnFailure(hr, "Failed to select BundleExtension nodes.");
+    // Select BootstrapperExtension nodes.
+    hr = XmlSelectNodes(pixnBundle, L"BootstrapperExtension", &pixnNodes);
+    ExitOnFailure(hr, "Failed to select BootstrapperExtension nodes.");
 
-    // Get BundleExtension node count.
+    // Get BootstrapperExtension node count.
     hr = pixnNodes->get_length((long*)&cNodes);
-    ExitOnFailure(hr, "Failed to get BundleExtension node count.");
+    ExitOnFailure(hr, "Failed to get BootstrapperExtension node count.");
 
     if (!cNodes)
     {
         ExitFunction();
     }
 
-    // Allocate memory for BundleExtensions.
+    // Allocate memory for BootstrapperExtensions.
     pBurnExtensions->rgExtensions = (BURN_EXTENSION*)MemAlloc(sizeof(BURN_EXTENSION) * cNodes, TRUE);
-    ExitOnNull(pBurnExtensions->rgExtensions, hr, E_OUTOFMEMORY, "Failed to allocate memory for BundleExtension structs.");
+    ExitOnNull(pBurnExtensions->rgExtensions, hr, E_OUTOFMEMORY, "Failed to allocate memory for BootstrapperExtension structs.");
 
     pBurnExtensions->cExtensions = cNodes;
 
@@ -64,7 +64,7 @@ EXTERN_C HRESULT BurnExtensionParseFromXml(
         ExitOnFailure(hr, "Failed to get @EntryPayloadSourcePath.");
 
         hr = PayloadFindEmbeddedBySourcePath(pBaPayloads->sdhPayloads, scz, &pExtension->pEntryPayload);
-        ExitOnFailure(hr, "Failed to find BundleExtension EntryPayload '%ls'.", pExtension->sczId);
+        ExitOnFailure(hr, "Failed to find BootstrapperExtension EntryPayload '%ls'.", pExtension->sczId);
 
         // prepare next iteration
         ReleaseNullObject(pixnNode);
@@ -81,7 +81,7 @@ LExit:
 }
 
 /*******************************************************************
- BurnExtensionUninitialize - 
+ BurnExtensionUninitialize -
 
 *******************************************************************/
 EXTERN_C void BurnExtensionUninitialize(
@@ -104,7 +104,7 @@ EXTERN_C void BurnExtensionUninitialize(
 }
 
 /*******************************************************************
- BurnExtensionLoad - 
+ BurnExtensionLoad -
 
 *******************************************************************/
 EXTERN_C HRESULT BurnExtensionLoad(
@@ -113,59 +113,59 @@ EXTERN_C HRESULT BurnExtensionLoad(
     )
 {
     HRESULT hr = S_OK;
-    LPWSTR sczBundleExtensionDataPath = NULL;
-    BUNDLE_EXTENSION_CREATE_ARGS args = { };
-    BUNDLE_EXTENSION_CREATE_RESULTS results = { };
+    LPWSTR sczBootstrapperExtensionDataPath = NULL;
+    BOOTSTRAPPER_EXTENSION_CREATE_ARGS args = { };
+    BOOTSTRAPPER_EXTENSION_CREATE_RESULTS results = { };
 
     if (!pBurnExtensions->rgExtensions || !pBurnExtensions->cExtensions)
     {
         ExitFunction();
     }
 
-    hr = PathConcat(pEngineContext->pEngineState->userExperience.sczTempDirectory, L"BundleExtensionData.xml", &sczBundleExtensionDataPath);
-    ExitOnFailure(hr, "Failed to get BundleExtensionDataPath.");
+    hr = PathConcat(pEngineContext->pEngineState->userExperience.sczTempDirectory, L"BootstrapperExtensionData.xml", &sczBootstrapperExtensionDataPath);
+    ExitOnFailure(hr, "Failed to get BootstrapperExtensionDataPath.");
 
     for (DWORD i = 0; i < pBurnExtensions->cExtensions; ++i)
     {
         BURN_EXTENSION* pExtension = &pBurnExtensions->rgExtensions[i];
 
-        memset(&args, 0, sizeof(BUNDLE_EXTENSION_CREATE_ARGS));
-        memset(&results, 0, sizeof(BUNDLE_EXTENSION_CREATE_RESULTS));
+        memset(&args, 0, sizeof(BOOTSTRAPPER_EXTENSION_CREATE_ARGS));
+        memset(&results, 0, sizeof(BOOTSTRAPPER_EXTENSION_CREATE_RESULTS));
 
-        args.cbSize = sizeof(BUNDLE_EXTENSION_CREATE_ARGS);
-        args.pfnBundleExtensionEngineProc = EngineForExtensionProc;
-        args.pvBundleExtensionEngineProcContext = pEngineContext;
+        args.cbSize = sizeof(BOOTSTRAPPER_EXTENSION_CREATE_ARGS);
+        args.pfnBootstrapperExtensionEngineProc = EngineForExtensionProc;
+        args.pvBootstrapperExtensionEngineProcContext = pEngineContext;
         args.qwEngineAPIVersion = MAKEQWORDVERSION(2021, 4, 27, 0);
         args.wzBootstrapperWorkingFolder = pEngineContext->pEngineState->userExperience.sczTempDirectory;
-        args.wzBundleExtensionDataPath = sczBundleExtensionDataPath;
+        args.wzBootstrapperExtensionDataPath = sczBootstrapperExtensionDataPath;
         args.wzExtensionId = pExtension->sczId;
 
-        results.cbSize = sizeof(BUNDLE_EXTENSION_CREATE_RESULTS);
+        results.cbSize = sizeof(BOOTSTRAPPER_EXTENSION_CREATE_RESULTS);
 
-        // Load BundleExtension DLL.
+        // Load BootstrapperExtension DLL.
         pExtension->hBextModule = ::LoadLibraryExW(pExtension->pEntryPayload->sczLocalFilePath, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
-        ExitOnNullWithLastError(pExtension->hBextModule, hr, "Failed to load BundleExtension DLL '%ls': '%ls'.", pExtension->sczId, pExtension->pEntryPayload->sczLocalFilePath);
+        ExitOnNullWithLastError(pExtension->hBextModule, hr, "Failed to load BootstrapperExtension DLL '%ls': '%ls'.", pExtension->sczId, pExtension->pEntryPayload->sczLocalFilePath);
 
-        // Get BundleExtensionCreate entry-point.
-        PFN_BUNDLE_EXTENSION_CREATE pfnCreate = (PFN_BUNDLE_EXTENSION_CREATE)::GetProcAddress(pExtension->hBextModule, "BundleExtensionCreate");
-        ExitOnNullWithLastError(pfnCreate, hr, "Failed to get BundleExtensionCreate entry-point '%ls'.", pExtension->sczId);
+        // Get BootstrapperExtensionCreate entry-point.
+        PFN_BOOTSTRAPPER_EXTENSION_CREATE pfnCreate = (PFN_BOOTSTRAPPER_EXTENSION_CREATE)::GetProcAddress(pExtension->hBextModule, "BootstrapperExtensionCreate");
+        ExitOnNullWithLastError(pfnCreate, hr, "Failed to get BootstrapperExtensionCreate entry-point '%ls'.", pExtension->sczId);
 
-        // Create BundleExtension.
+        // Create BootstrapperExtension.
         hr = pfnCreate(&args, &results);
-        ExitOnFailure(hr, "Failed to create BundleExtension '%ls'.", pExtension->sczId);
+        ExitOnFailure(hr, "Failed to create BootstrapperExtension '%ls'.", pExtension->sczId);
 
-        pExtension->pfnBurnExtensionProc = results.pfnBundleExtensionProc;
-        pExtension->pvBurnExtensionProcContext = results.pvBundleExtensionProcContext;
+        pExtension->pfnBurnExtensionProc = results.pfnBootstrapperExtensionProc;
+        pExtension->pvBurnExtensionProcContext = results.pvBootstrapperExtensionProcContext;
     }
 
 LExit:
-    ReleaseStr(sczBundleExtensionDataPath);
+    ReleaseStr(sczBootstrapperExtensionDataPath);
 
     return hr;
 }
 
 /*******************************************************************
- BurnExtensionUnload - 
+ BurnExtensionUnload -
 
 *******************************************************************/
 EXTERN_C void BurnExtensionUnload(
@@ -182,18 +182,18 @@ EXTERN_C void BurnExtensionUnload(
 
             if (pExtension->hBextModule)
             {
-                // Get BundleExtensionDestroy entry-point and call it if it exists.
-                PFN_BUNDLE_EXTENSION_DESTROY pfnDestroy = (PFN_BUNDLE_EXTENSION_DESTROY)::GetProcAddress(pExtension->hBextModule, "BundleExtensionDestroy");
+                // Get BootstrapperExtensionDestroy entry-point and call it if it exists.
+                PFN_BOOTSTRAPPER_EXTENSION_DESTROY pfnDestroy = (PFN_BOOTSTRAPPER_EXTENSION_DESTROY)::GetProcAddress(pExtension->hBextModule, "BootstrapperExtensionDestroy");
                 if (pfnDestroy)
                 {
                     pfnDestroy();
                 }
 
-                // Free BundleExtension DLL.
+                // Free BootstrapperExtension DLL.
                 if (!::FreeLibrary(pExtension->hBextModule))
                 {
                     hr = HRESULT_FROM_WIN32(::GetLastError());
-                    TraceError(hr, "Failed to unload BundleExtension DLL.");
+                    TraceError(hr, "Failed to unload BootstrapperExtension DLL.");
                 }
                 pExtension->hBextModule = NULL;
             }
@@ -234,8 +234,8 @@ EXTERN_C BEEAPI BurnExtensionPerformSearch(
     )
 {
     HRESULT hr = S_OK;
-    BUNDLE_EXTENSION_SEARCH_ARGS args = { };
-    BUNDLE_EXTENSION_SEARCH_RESULTS results = { };
+    BOOTSTRAPPER_EXTENSION_SEARCH_ARGS args = { };
+    BOOTSTRAPPER_EXTENSION_SEARCH_RESULTS results = { };
 
     args.cbSize = sizeof(args);
     args.wzId = wzSearchId;
@@ -243,8 +243,8 @@ EXTERN_C BEEAPI BurnExtensionPerformSearch(
 
     results.cbSize = sizeof(results);
 
-    hr = SendRequiredBextMessage(pExtension, BUNDLE_EXTENSION_MESSAGE_SEARCH, &args, &results);
-    ExitOnFailure(hr, "BundleExtension '%ls' Search '%ls' failed.", pExtension->sczId, wzSearchId);
+    hr = SendRequiredBextMessage(pExtension, BOOTSTRAPPER_EXTENSION_MESSAGE_SEARCH, &args, &results);
+    ExitOnFailure(hr, "BootstrapperExtension '%ls' Search '%ls' failed.", pExtension->sczId, wzSearchId);
 
 LExit:
     return hr;
@@ -252,7 +252,7 @@ LExit:
 
 static HRESULT SendRequiredBextMessage(
     __in BURN_EXTENSION* pExtension,
-    __in BUNDLE_EXTENSION_MESSAGE message,
+    __in BOOTSTRAPPER_EXTENSION_MESSAGE message,
     __in const LPVOID pvArgs,
     __inout LPVOID pvResults
     )
diff --git a/src/burn/engine/burnextension.h b/src/burn/engine/burnextension.h
index 3529ef38..d6926647 100644
--- a/src/burn/engine/burnextension.h
+++ b/src/burn/engine/burnextension.h
@@ -18,7 +18,7 @@ typedef struct _BURN_EXTENSION
     BURN_PAYLOAD* pEntryPayload;
 
     HMODULE hBextModule;
-    PFN_BUNDLE_EXTENSION_PROC pfnBurnExtensionProc;
+    PFN_BOOTSTRAPPER_EXTENSION_PROC pfnBurnExtensionProc;
     LPVOID pvBurnExtensionProcContext;
 } BURN_EXTENSION;
 
diff --git a/src/burn/engine/engine.cpp b/src/burn/engine/engine.cpp
index 9daa18a1..619ff0d1 100644
--- a/src/burn/engine/engine.cpp
+++ b/src/burn/engine/engine.cpp
@@ -535,7 +535,7 @@ static HRESULT RunNormal(
 
     // Load the extensions.
     hr = BurnExtensionLoad(&pEngineState->extensions, &extensionEngineContext);
-    ExitOnFailure(hr, "Failed to load BundleExtensions.");
+    ExitOnFailure(hr, "Failed to load BootstrapperExtensions.");
 
     // The secondary bootstrapper application only gets one chance to execute. That means
     // first time through we run the primary bootstrapper application and on reload we run
diff --git a/src/burn/engine/engine.vcxproj b/src/burn/engine/engine.vcxproj
index 73985d51..62e03941 100644
--- a/src/burn/engine/engine.vcxproj
+++ b/src/burn/engine/engine.vcxproj
@@ -104,8 +104,8 @@
     <ClInclude Include="approvedexe.h" />
     <ClInclude Include="..\..\api\burn\inc\BootstrapperApplication.h" />
     <ClInclude Include="..\..\api\burn\inc\BootstrapperEngine.h" />
-    <ClInclude Include="..\..\api\burn\inc\BundleExtension.h" />
-    <ClInclude Include="..\..\api\burn\inc\BundleExtensionEngine.h" />
+    <ClInclude Include="..\..\api\burn\inc\BootstrapperExtension.h" />
+    <ClInclude Include="..\..\api\burn\inc\BootstrapperExtensionEngine.h" />
     <ClInclude Include="ba.h" />
     <ClInclude Include="bacallback.h" />
     <ClInclude Include="bundlepackageengine.h" />
diff --git a/src/burn/engine/precomp.h b/src/burn/engine/precomp.h
index 3b9693ff..348c78ce 100644
--- a/src/burn/engine/precomp.h
+++ b/src/burn/engine/precomp.h
@@ -62,7 +62,7 @@
 #include <butil.h>
 
 #include "BootstrapperApplication.h"
-#include "BundleExtension.h"
+#include "BootstrapperExtension.h"
 
 #include "platform.h"
 #include "variant.h"
diff --git a/src/burn/test/BurnUnitTest/TestData/PlanTest/BasicFunctionality_BundleA_manifest.xml b/src/burn/test/BurnUnitTest/TestData/PlanTest/BasicFunctionality_BundleA_manifest.xml
index f4cc2820..975a3805 100644
--- a/src/burn/test/BurnUnitTest/TestData/PlanTest/BasicFunctionality_BundleA_manifest.xml
+++ b/src/burn/test/BurnUnitTest/TestData/PlanTest/BasicFunctionality_BundleA_manifest.xml
@@ -8,8 +8,8 @@
         <Payload Id="pay00kQk8rVqabvZJ20B.w1mpx7GDo" FilePath="thm.xml" FileSize="7980" Hash="7A88582165EEE4CA1D23F1B7DD58F8023552E049" Packaging="embedded" SourcePath="u0" />
         <Payload Id="payI2_GHsNfx8LnXWC6YRRG.VuyhI4" FilePath="thm.wxl" FileSize="4194" Hash="906294A9515835C5C8F4C5E86A32E179041C90DD" Packaging="embedded" SourcePath="u1" />
         <Payload Id="payjqSD44latbvJnf4vAQuVMUST73A" FilePath="logo.png" FileSize="852" Hash="239F10674BF6022854C1F1BF7C91955BDE34D3E4" Packaging="embedded" SourcePath="u2" />
-        <Payload Id="uxTxMXPVMXwQrPTMIGa5WGt93w0Ns" FilePath="BootstrapperApplicationData.xml" FileSize="3698" Hash="AADECC6EF50E87D0642A5667CD612EF53E2CFB9A" Packaging="embedded" SourcePath="u4" />
-        <Payload Id="uxYRbgitOs0K878jn5L_z7LdJ21KI" FilePath="BundleExtensionData.xml" FileSize="252" Hash="86688B13D3364ADB90BBA552F544D4D546AFD63D" Packaging="embedded" SourcePath="u5" />
+        <Payload Id="uxmKgAFS4cS31ZH_Myfqo5J4kHixQ" FilePath="BootstrapperApplicationData.xml" FileSize="3698" Hash="AADECC6EF50E87D0642A5667CD612EF53E2CFB9A" Packaging="embedded" SourcePath="u4" />
+        <Payload Id="uxYRbgitOs0K878jn5L_z7LdJ21KI" FilePath="BootstrapperExtensionData.xml" FileSize="252" Hash="86688B13D3364ADB90BBA552F544D4D546AFD63D" Packaging="embedded" SourcePath="u5" />
     </UX>
     <Container Id="WixAttachedContainer" FileSize="6959" Hash="4FC82B3432B5892D2A4EC593264A916DBDA9CE45" FilePath="BundleA.exe" AttachedIndex="1" Attached="yes" Primary="yes" />
     <Payload Id="PackageA" FilePath="PackageA.msi" FileSize="32768" Hash="89C61F8A105A81B08036401152A1FDE67CDC0158" Packaging="embedded" SourcePath="a0" Container="WixAttachedContainer" />
diff --git a/src/burn/test/BurnUnitTest/TestData/PlanTest/BundlePackage_Multiple_manifest.xml b/src/burn/test/BurnUnitTest/TestData/PlanTest/BundlePackage_Multiple_manifest.xml
index b75899cc..a8696537 100644
--- a/src/burn/test/BurnUnitTest/TestData/PlanTest/BundlePackage_Multiple_manifest.xml
+++ b/src/burn/test/BurnUnitTest/TestData/PlanTest/BundlePackage_Multiple_manifest.xml
@@ -38,8 +38,8 @@
         <Payload Id="payqeWUzIVaEqjuRXN0z8ECC3Y4tCc" FilePath="3082\mbapreq.wxl" SourcePath="u29" />
         <Payload Id="paylfeHEjJSSTnNzY9QMZM2Ye3Ipy4" FilePath="mbapreq.dll" SourcePath="u31" />
         <Payload Id="payDPxs6uy8nbky.R7zhir2RRAfc.c" FilePath="WixToolset.Mba.Host.dll" SourcePath="u32" />
-        <Payload Id="uxTxMXPVMXwQrPTMIGa5WGt93w0Ns" FilePath="BootstrapperApplicationData.xml" SourcePath="u33" />
-        <Payload Id="uxYRbgitOs0K878jn5L_z7LdJ21KI" FilePath="BundleExtensionData.xml" SourcePath="u34" />
+        <Payload Id="uxmKgAFS4cS31ZH_Myfqo5J4kHixQ" FilePath="BootstrapperApplicationData.xml" SourcePath="u33" />
+        <Payload Id="uxYRbgitOs0K878jn5L_z7LdJ21KI" FilePath="BootstrapperExtensionData.xml" SourcePath="u34" />
     </UX>
     <Container Id="WixAttachedContainer" FileSize="15696370" Hash="0F9966B421400E481D394DB4C4D7F0F92548E5BEB79B98880C926E817E8C1F381EC8A17053E2E66AE7132A3C9ECE441629E6A1FB3452C5C9282280C40252F141" FilePath="MultipleBundlePackagesBundle.exe" AttachedIndex="1" Attached="yes" Primary="yes" />
     <Payload Id="NetFx48Web" FilePath="redist\ndp48-web.exe" FileSize="1439328" CertificateRootPublicKeyIdentifier="F49F9B33E25E33CCA0BFB15A62B7C29FFAB3880B" CertificateRootThumbprint="ABDCA79AF9DD48A0EA702AD45260B3C03093FB4B" DownloadUrl="https://go.microsoft.com/fwlink/?LinkId=2085155" Packaging="external" SourcePath="redist\ndp48-web.exe" />
diff --git a/src/burn/test/BurnUnitTest/TestData/PlanTest/ExePackage_PerUserArpEntry_manifest.xml b/src/burn/test/BurnUnitTest/TestData/PlanTest/ExePackage_PerUserArpEntry_manifest.xml
index 680f6c5f..167bfbbb 100644
--- a/src/burn/test/BurnUnitTest/TestData/PlanTest/ExePackage_PerUserArpEntry_manifest.xml
+++ b/src/burn/test/BurnUnitTest/TestData/PlanTest/ExePackage_PerUserArpEntry_manifest.xml
@@ -38,8 +38,8 @@
         <Payload Id="payqeWUzIVaEqjuRXN0z8ECC3Y4tCc" FilePath="3082\mbapreq.wxl" SourcePath="u29" />
         <Payload Id="paylfeHEjJSSTnNzY9QMZM2Ye3Ipy4" FilePath="mbapreq.dll" SourcePath="u31" />
         <Payload Id="payDPxs6uy8nbky.R7zhir2RRAfc.c" FilePath="WixToolset.Mba.Host.dll" SourcePath="u32" />
-        <Payload Id="uxTxMXPVMXwQrPTMIGa5WGt93w0Ns" FilePath="BootstrapperApplicationData.xml" SourcePath="u33" />
-        <Payload Id="uxYRbgitOs0K878jn5L_z7LdJ21KI" FilePath="BundleExtensionData.xml" SourcePath="u34" />
+        <Payload Id="uxmKgAFS4cS31ZH_Myfqo5J4kHixQ" FilePath="BootstrapperApplicationData.xml" SourcePath="u33" />
+        <Payload Id="uxYRbgitOs0K878jn5L_z7LdJ21KI" FilePath="BootstrapperExtensionData.xml" SourcePath="u34" />
     </UX>
     <Container Id="WixAttachedContainer" FileSize="24029" Hash="E54459AA91F60561F8AFBBCB5AEA19DB0377DB53FC3B4944E46995C2D5F97FE23E7487148DC25C14E7888CF841664EA65540529DB5E191591A83B30075098506" FilePath="PerUserArpEntryExePackage.exe" AttachedIndex="1" Attached="yes" Primary="yes" />
     <Payload Id="NetFx48Web" FilePath="redist\ndp48-web.exe" FileSize="1439328" CertificateRootPublicKeyIdentifier="F49F9B33E25E33CCA0BFB15A62B7C29FFAB3880B" CertificateRootThumbprint="ABDCA79AF9DD48A0EA702AD45260B3C03093FB4B" DownloadUrl="https://go.microsoft.com/fwlink/?LinkId=2085155" Packaging="external" SourcePath="redist\ndp48-web.exe" />
diff --git a/src/burn/test/BurnUnitTest/TestData/PlanTest/Failure_BundleD_manifest.xml b/src/burn/test/BurnUnitTest/TestData/PlanTest/Failure_BundleD_manifest.xml
index bfe1dfee..4e15fddb 100644
--- a/src/burn/test/BurnUnitTest/TestData/PlanTest/Failure_BundleD_manifest.xml
+++ b/src/burn/test/BurnUnitTest/TestData/PlanTest/Failure_BundleD_manifest.xml
@@ -39,8 +39,8 @@
         <Payload Id="payqeWUzIVaEqjuRXN0z8ECC3Y4tCc" FilePath="3082\mbapreq.wxl" SourcePath="u29" />
         <Payload Id="paylfeHEjJSSTnNzY9QMZM2Ye3Ipy4" FilePath="mbapreq.dll" SourcePath="u31" />
         <Payload Id="payDPxs6uy8nbky.R7zhir2RRAfc.c" FilePath="WixToolset.Mba.Host.dll" SourcePath="u32" />
-        <Payload Id="uxTxMXPVMXwQrPTMIGa5WGt93w0Ns" FilePath="BootstrapperApplicationData.xml" SourcePath="u33" />
-        <Payload Id="uxYRbgitOs0K878jn5L_z7LdJ21KI" FilePath="BundleExtensionData.xml" SourcePath="u34" />
+        <Payload Id="uxmKgAFS4cS31ZH_Myfqo5J4kHixQ" FilePath="BootstrapperApplicationData.xml" SourcePath="u33" />
+        <Payload Id="uxYRbgitOs0K878jn5L_z7LdJ21KI" FilePath="BootstrapperExtensionData.xml" SourcePath="u34" />
     </UX>
     <Container Id="WixAttachedContainer" FileSize="24029" Hash="03F9C95A2ADA5563D3D937C0161F22A76E12F2F0AF2AA6BE567292D0AB122E2C42990E97CA9C1EE9A5F43A571B01C4ED7A3EA5759A6836AC8BFD959D7FFDCB18" FilePath="BundleD.exe" AttachedIndex="1" Attached="yes" Primary="yes" />
     <Payload Id="NetFx48Web" FilePath="redist\ndp48-web.exe" FileSize="1439328" CertificateRootPublicKeyIdentifier="F49F9B33E25E33CCA0BFB15A62B7C29FFAB3880B" CertificateRootThumbprint="ABDCA79AF9DD48A0EA702AD45260B3C03093FB4B" DownloadUrl="https://go.microsoft.com/fwlink/?LinkId=2085155" Packaging="external" SourcePath="redist\ndp48-web.exe" />
diff --git a/src/burn/test/BurnUnitTest/TestData/PlanTest/MsiTransaction_BundleAv1_manifest.xml b/src/burn/test/BurnUnitTest/TestData/PlanTest/MsiTransaction_BundleAv1_manifest.xml
index 73c6078d..c9294707 100644
--- a/src/burn/test/BurnUnitTest/TestData/PlanTest/MsiTransaction_BundleAv1_manifest.xml
+++ b/src/burn/test/BurnUnitTest/TestData/PlanTest/MsiTransaction_BundleAv1_manifest.xml
@@ -8,8 +8,8 @@
         <Payload Id="pay00kQk8rVqabvZJ20B.w1mpx7GDo" FilePath="thm.xml" FileSize="7980" Hash="7A88582165EEE4CA1D23F1B7DD58F8023552E049" Packaging="embedded" SourcePath="u0" />
         <Payload Id="payI2_GHsNfx8LnXWC6YRRG.VuyhI4" FilePath="thm.wxl" FileSize="4194" Hash="906294A9515835C5C8F4C5E86A32E179041C90DD" Packaging="embedded" SourcePath="u1" />
         <Payload Id="payjqSD44latbvJnf4vAQuVMUST73A" FilePath="logo.png" FileSize="852" Hash="239F10674BF6022854C1F1BF7C91955BDE34D3E4" Packaging="embedded" SourcePath="u2" />
-        <Payload Id="uxTxMXPVMXwQrPTMIGa5WGt93w0Ns" FilePath="BootstrapperApplicationData.xml" FileSize="6742" Hash="E124C9502891F1277A47D1AEC0F1755BA605E6E3" Packaging="embedded" SourcePath="u4" />
-        <Payload Id="uxYRbgitOs0K878jn5L_z7LdJ21KI" FilePath="BundleExtensionData.xml" FileSize="252" Hash="86688B13D3364ADB90BBA552F544D4D546AFD63D" Packaging="embedded" SourcePath="u5" />
+        <Payload Id="uxmKgAFS4cS31ZH_Myfqo5J4kHixQ" FilePath="BootstrapperApplicationData.xml" FileSize="6742" Hash="E124C9502891F1277A47D1AEC0F1755BA605E6E3" Packaging="embedded" SourcePath="u4" />
+        <Payload Id="uxYRbgitOs0K878jn5L_z7LdJ21KI" FilePath="BootstrapperExtensionData.xml" FileSize="252" Hash="86688B13D3364ADB90BBA552F544D4D546AFD63D" Packaging="embedded" SourcePath="u5" />
     </UX>
     <Container Id="WixAttachedContainer" FileSize="16403" Hash="AABC770A92954AE4234A322A3621333B3FDDE225" FilePath="BundleAv1.exe" AttachedIndex="1" Attached="yes" Primary="yes" />
     <Payload Id="PackageA" FilePath="PackageA.msi" FileSize="32768" Hash="C763E00CD117F79643F58442B87F51721554686D" Packaging="embedded" SourcePath="a0" Container="WixAttachedContainer" />
diff --git a/src/burn/test/BurnUnitTest/TestData/PlanTest/MsuPackageFixture_manifest.xml b/src/burn/test/BurnUnitTest/TestData/PlanTest/MsuPackageFixture_manifest.xml
index 675183b1..824cf489 100644
--- a/src/burn/test/BurnUnitTest/TestData/PlanTest/MsuPackageFixture_manifest.xml
+++ b/src/burn/test/BurnUnitTest/TestData/PlanTest/MsuPackageFixture_manifest.xml
@@ -4,8 +4,8 @@
     <RelatedBundle Id="{B94478B1-E1F3-4700-9CE8-6AA090854AEC}" Action="Upgrade" />
     <UX PrimaryPayloadId="payaQenPi7_8hq6T._EXtBW0NvR7gA">
         <Payload Id="payaQenPi7_8hq6T._EXtBW0NvR7gA" FilePath="fakeba.exe" SourcePath="u0" />
-        <Payload Id="uxTxMXPVMXwQrPTMIGa5WGt93w0Ns" FilePath="BootstrapperApplicationData.xml" SourcePath="u1" />
-        <Payload Id="uxYRbgitOs0K878jn5L_z7LdJ21KI" FilePath="BundleExtensionData.xml" SourcePath="u2" />
+        <Payload Id="uxmKgAFS4cS31ZH_Myfqo5J4kHixQ" FilePath="BootstrapperApplicationData.xml" SourcePath="u1" />
+        <Payload Id="uxYRbgitOs0K878jn5L_z7LdJ21KI" FilePath="BootstrapperExtensionData.xml" SourcePath="u2" />
     </UX>
     <Container Id="WixAttachedContainer" FileSize="119" Hash="06D28293FD57CD231E125EF9C82418A488928A98832A6937A77A3283A17A5C37F8D619C51759319A57E8F8A948FA73E8C5814185A0114130F3213AB268073555" FilePath="test.exe" AttachedIndex="1" Attached="yes" Primary="yes" />
     <Payload Id="test.msu" FilePath="test.msu" FileSize="28" Hash="B040F02D2F90E04E9AFBDC91C00CEB5DF97D48E205D96DC0A44E10AF8870794DAE62CA70224F12BE9112AA730BBE470CA81FB5617AAC690E832F3F84510E92BA" Packaging="embedded" SourcePath="a0" Container="WixAttachedContainer" />
diff --git a/src/burn/test/BurnUnitTest/TestData/PlanTest/Slipstream_BundleA_manifest.xml b/src/burn/test/BurnUnitTest/TestData/PlanTest/Slipstream_BundleA_manifest.xml
index c5ca03b6..d1fd96bb 100644
--- a/src/burn/test/BurnUnitTest/TestData/PlanTest/Slipstream_BundleA_manifest.xml
+++ b/src/burn/test/BurnUnitTest/TestData/PlanTest/Slipstream_BundleA_manifest.xml
@@ -38,8 +38,8 @@
         <Payload Id="payqeWUzIVaEqjuRXN0z8ECC3Y4tCc" FilePath="3082\mbapreq.wxl" FileSize="2369" Hash="39C07C31077AAFDC0DD208273AA41654CAD80FDD" Packaging="embedded" SourcePath="u29" />
         <Payload Id="paylfeHEjJSSTnNzY9QMZM2Ye3Ipy4" FilePath="mbapreq.dll" FileSize="245760" Hash="6499FA21D178131DDE13A4EF44ABEC32E91D65D4" Packaging="embedded" SourcePath="u31" />
         <Payload Id="payDPxs6uy8nbky.R7zhir2RRAfc.c" FilePath="WixToolset.Mba.Host.dll" FileSize="11264" Hash="9E6452891E401EB211DD41550A09FDF98EC0992F" Packaging="embedded" SourcePath="u32" />
-        <Payload Id="uxTxMXPVMXwQrPTMIGa5WGt93w0Ns" FilePath="BootstrapperApplicationData.xml" FileSize="14292" Hash="CDF09A0723F4F33C13670BBAFCFFA7E660E15DFC" Packaging="embedded" SourcePath="u33" />
-        <Payload Id="uxYRbgitOs0K878jn5L_z7LdJ21KI" FilePath="BundleExtensionData.xml" FileSize="252" Hash="86688B13D3364ADB90BBA552F544D4D546AFD63D" Packaging="embedded" SourcePath="u34" />
+        <Payload Id="uxmKgAFS4cS31ZH_Myfqo5J4kHixQ" FilePath="BootstrapperApplicationData.xml" FileSize="14292" Hash="CDF09A0723F4F33C13670BBAFCFFA7E660E15DFC" Packaging="embedded" SourcePath="u33" />
+        <Payload Id="uxYRbgitOs0K878jn5L_z7LdJ21KI" FilePath="BootstrapperExtensionData.xml" FileSize="252" Hash="86688B13D3364ADB90BBA552F544D4D546AFD63D" Packaging="embedded" SourcePath="u34" />
     </UX>
     <Payload Id="NetFx48Web" FilePath="redist\ndp48-web.exe" FileSize="1479400" Hash="5A84A8E612E270E27D0061D58DB6B470153BE1F9" DownloadUrl="https://go.microsoft.com/fwlink/?LinkId=2085155" Packaging="external" SourcePath="redist\ndp48-web.exe" />
     <Payload Id="PackageA" FilePath="PackageAv1.msi" FileSize="32768" Hash="2369B16B7219B3C834DFBC5D2AF8B2EF8803D43D" Packaging="external" SourcePath="PackageAv1.msi" />
diff --git a/src/burn/test/BurnUnitTest/TestData/PlanTest/Slipstream_BundleA_modified_manifest.xml b/src/burn/test/BurnUnitTest/TestData/PlanTest/Slipstream_BundleA_modified_manifest.xml
index 52091ebd..2f829586 100644
--- a/src/burn/test/BurnUnitTest/TestData/PlanTest/Slipstream_BundleA_modified_manifest.xml
+++ b/src/burn/test/BurnUnitTest/TestData/PlanTest/Slipstream_BundleA_modified_manifest.xml
@@ -38,8 +38,8 @@
         <Payload Id="payqeWUzIVaEqjuRXN0z8ECC3Y4tCc" FilePath="3082\mbapreq.wxl" FileSize="2369" Hash="39C07C31077AAFDC0DD208273AA41654CAD80FDD" Packaging="embedded" SourcePath="u29" />
         <Payload Id="paylfeHEjJSSTnNzY9QMZM2Ye3Ipy4" FilePath="mbapreq.dll" FileSize="245760" Hash="6499FA21D178131DDE13A4EF44ABEC32E91D65D4" Packaging="embedded" SourcePath="u31" />
         <Payload Id="payDPxs6uy8nbky.R7zhir2RRAfc.c" FilePath="WixToolset.Mba.Host.dll" FileSize="11264" Hash="9E6452891E401EB211DD41550A09FDF98EC0992F" Packaging="embedded" SourcePath="u32" />
-        <Payload Id="uxTxMXPVMXwQrPTMIGa5WGt93w0Ns" FilePath="BootstrapperApplicationData.xml" FileSize="14292" Hash="CDF09A0723F4F33C13670BBAFCFFA7E660E15DFC" Packaging="embedded" SourcePath="u33" />
-        <Payload Id="uxYRbgitOs0K878jn5L_z7LdJ21KI" FilePath="BundleExtensionData.xml" FileSize="252" Hash="86688B13D3364ADB90BBA552F544D4D546AFD63D" Packaging="embedded" SourcePath="u34" />
+        <Payload Id="uxmKgAFS4cS31ZH_Myfqo5J4kHixQ" FilePath="BootstrapperApplicationData.xml" FileSize="14292" Hash="CDF09A0723F4F33C13670BBAFCFFA7E660E15DFC" Packaging="embedded" SourcePath="u33" />
+        <Payload Id="uxYRbgitOs0K878jn5L_z7LdJ21KI" FilePath="BootstrapperExtensionData.xml" FileSize="252" Hash="86688B13D3364ADB90BBA552F544D4D546AFD63D" Packaging="embedded" SourcePath="u34" />
     </UX>
     <Payload Id="NetFx48Web" FilePath="redist\ndp48-web.exe" FileSize="1479400" Hash="5A84A8E612E270E27D0061D58DB6B470153BE1F9" DownloadUrl="https://go.microsoft.com/fwlink/?LinkId=2085155" Packaging="external" SourcePath="redist\ndp48-web.exe" />
     <Payload Id="PackageA" FilePath="PackageAv1.msi" FileSize="32768" Hash="2369B16B7219B3C834DFBC5D2AF8B2EF8803D43D" Packaging="external" SourcePath="PackageAv1.msi" />
diff --git a/src/burn/test/BurnUnitTest/precomp.h b/src/burn/test/BurnUnitTest/precomp.h
index 0f98480a..7a84dd41 100644
--- a/src/burn/test/BurnUnitTest/precomp.h
+++ b/src/burn/test/BurnUnitTest/precomp.h
@@ -38,7 +38,7 @@
 #include <butil.h>
 
 #include "BootstrapperApplication.h"
-#include "BundleExtension.h"
+#include "BootstrapperExtension.h"
 
 #include "platform.h"
 #include "variant.h"
diff --git a/src/clean.cmd b/src/clean.cmd
index f2f10cd3..6164a8f9 100644
--- a/src/clean.cmd
+++ b/src/clean.cmd
@@ -22,6 +22,7 @@ if exist "%_NUGET_CACHE%\wixinternal.testsupport" rd /s/q "%_NUGET_CACHE%\wixint
 if exist "%_NUGET_CACHE%\wixinternal.core.testpackage" rd /s/q "%_NUGET_CACHE%\wixinternal.core.testpackage"
 if exist "%_NUGET_CACHE%\wixtoolset.bal.wixext" rd /s/q "%_NUGET_CACHE%\wixtoolset.bal.wixext"
 if exist "%_NUGET_CACHE%\wixtoolset.bootstrapperapplications.wixext" rd /s/q "%_NUGET_CACHE%\wixtoolset.bootstrapperapplications.wixext"
+if exist "%_NUGET_CACHE%\wixtoolset.bootstrapperextensionapi" rd /s/q "%_NUGET_CACHE%\wixtoolset.bootstrapperextensionapi"
 if exist "%_NUGET_CACHE%\wixtoolset.bextutil" rd /s/q "%_NUGET_CACHE%\wixtoolset.bextutil"
 if exist "%_NUGET_CACHE%\wixtoolset.burn" rd /s/q "%_NUGET_CACHE%\wixtoolset.burn"
 if exist "%_NUGET_CACHE%\wixtoolset.complus.wixext" rd /s/q "%_NUGET_CACHE%\wixtoolset.complus.wixext"
diff --git a/src/ext/NetFx/be/NetfxBundleExtension.cpp b/src/ext/NetFx/be/NetfxBootstrapperExtension.cpp
index 838a97c1..ab30e378 100644
--- a/src/ext/NetFx/be/NetfxBundleExtension.cpp
+++ b/src/ext/NetFx/be/NetfxBootstrapperExtension.cpp
@@ -1,11 +1,11 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
 
 #include "precomp.h"
-#include "BextBaseBundleExtension.h"
+#include "BextBaseBootstrapperExtension.h"
 
-class CWixNetfxBundleExtension : public CBextBaseBundleExtension
+class CWixNetfxBootstrapperExtension : public CBextBaseBootstrapperExtension
 {
-public: // IBundleExtension
+public: // IBootstrapperExtension
     virtual STDMETHODIMP Search(
         __in LPCWSTR wzId,
         __in LPCWSTR wzVariable
@@ -18,18 +18,18 @@ public: // IBundleExtension
         return hr;
     }
 
-public: //CBextBaseBundleExtension
+public: //CBextBaseBootstrapperExtension
     virtual STDMETHODIMP Initialize(
-        __in const BUNDLE_EXTENSION_CREATE_ARGS* pCreateArgs
+        __in const BOOTSTRAPPER_EXTENSION_CREATE_ARGS* pCreateArgs
         )
     {
         HRESULT hr = S_OK;
         LPWSTR sczModulePath = NULL;
         IXMLDOMDocument* pixdManifest = NULL;
-        IXMLDOMNode* pixnBundleExtension = NULL;
+        IXMLDOMNode* pixnBootstrapperExtension = NULL;
 
         hr = __super::Initialize(pCreateArgs);
-        BextExitOnFailure(hr, "CBextBaseBundleExtension initialization failed.");
+        BextExitOnFailure(hr, "CBextBaseBootstrapperExtension initialization failed.");
 
         hr = PathForCurrentProcess(&sczModulePath, m_hInstance);
         BextExitOnFailure(hr, "Failed to get bundle extension path.");
@@ -37,17 +37,17 @@ public: //CBextBaseBundleExtension
         hr = PathGetDirectory(sczModulePath, &m_sczBaseDirectory);
         BextExitOnFailure(hr, "Failed to get bundle extension base directory.");
 
-        hr = XmlLoadDocumentFromFile(m_sczBundleExtensionDataPath, &pixdManifest);
-        BextExitOnFailure(hr, "Failed to load bundle extension manifest from path: %ls", m_sczBundleExtensionDataPath);
+        hr = XmlLoadDocumentFromFile(m_sczBootstrapperExtensionDataPath, &pixdManifest);
+        BextExitOnFailure(hr, "Failed to load bundle extension manifest from path: %ls", m_sczBootstrapperExtensionDataPath);
 
-        hr = BextGetBundleExtensionDataNode(pixdManifest, NETFX_BUNDLE_EXTENSION_ID, &pixnBundleExtension);
-        BextExitOnFailure(hr, "Failed to get BundleExtension '%ls'", NETFX_BUNDLE_EXTENSION_ID);
+        hr = BextGetBootstrapperExtensionDataNode(pixdManifest, NETFX_BOOTSTRAPPER_EXTENSION_ID, &pixnBootstrapperExtension);
+        BextExitOnFailure(hr, "Failed to get BootstrapperExtension '%ls'", NETFX_BOOTSTRAPPER_EXTENSION_ID);
 
-        hr = NetfxSearchParseFromXml(&m_searches, pixnBundleExtension);
+        hr = NetfxSearchParseFromXml(&m_searches, pixnBootstrapperExtension);
         BextExitOnFailure(hr, "Failed to parse searches from bundle extension manifest.");
 
     LExit:
-        ReleaseObject(pixnBundleExtension);
+        ReleaseObject(pixnBootstrapperExtension);
         ReleaseObject(pixdManifest);
         ReleaseStr(sczModulePath);
 
@@ -55,17 +55,17 @@ public: //CBextBaseBundleExtension
     }
 
 public:
-    CWixNetfxBundleExtension(
+    CWixNetfxBootstrapperExtension(
         __in HINSTANCE hInstance,
-        __in IBundleExtensionEngine* pEngine
-        ) : CBextBaseBundleExtension(pEngine)
+        __in IBootstrapperExtensionEngine* pEngine
+        ) : CBextBaseBootstrapperExtension(pEngine)
     {
         m_searches = { };
         m_hInstance = hInstance;
         m_sczBaseDirectory = NULL;
     }
 
-    ~CWixNetfxBundleExtension()
+    ~CWixNetfxBootstrapperExtension()
     {
         NetfxSearchUninitialize(&m_searches);
         ReleaseStr(m_sczBaseDirectory);
@@ -77,23 +77,23 @@ private:
     LPWSTR m_sczBaseDirectory;
 };
 
-HRESULT NetfxBundleExtensionCreate(
+HRESULT NetfxBootstrapperExtensionCreate(
     __in HINSTANCE hInstance,
-    __in IBundleExtensionEngine* pEngine,
-    __in const BUNDLE_EXTENSION_CREATE_ARGS* pArgs,
-    __out IBundleExtension** ppBundleExtension
+    __in IBootstrapperExtensionEngine* pEngine,
+    __in const BOOTSTRAPPER_EXTENSION_CREATE_ARGS* pArgs,
+    __out IBootstrapperExtension** ppBootstrapperExtension
     )
 {
     HRESULT hr = S_OK;
-    CWixNetfxBundleExtension* pExtension = NULL;
+    CWixNetfxBootstrapperExtension* pExtension = NULL;
 
-    pExtension = new CWixNetfxBundleExtension(hInstance, pEngine);
-    BextExitOnNull(pExtension, hr, E_OUTOFMEMORY, "Failed to create new CWixNetfxBundleExtension.");
+    pExtension = new CWixNetfxBootstrapperExtension(hInstance, pEngine);
+    BextExitOnNull(pExtension, hr, E_OUTOFMEMORY, "Failed to create new CWixNetfxBootstrapperExtension.");
 
     hr = pExtension->Initialize(pArgs);
-    BextExitOnFailure(hr, "CWixNetfxBundleExtension initialization failed.");
+    BextExitOnFailure(hr, "CWixNetfxBootstrapperExtension initialization failed.");
 
-    *ppBundleExtension = pExtension;
+    *ppBootstrapperExtension = pExtension;
     pExtension = NULL;
 
 LExit:
diff --git a/src/ext/NetFx/be/NetfxBootstrapperExtension.h b/src/ext/NetFx/be/NetfxBootstrapperExtension.h
new file mode 100644
index 00000000..36563dae
--- /dev/null
+++ b/src/ext/NetFx/be/NetfxBootstrapperExtension.h
@@ -0,0 +1,17 @@
+#pragma once
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+
+// constants
+
+#define NETFX_BOOTSTRAPPER_EXTENSION_ID BOOTSTRAPPER_EXTENSION_DECORATION(L"NetfxBootstrapperExtension")
+
+
+// function declarations
+
+HRESULT NetfxBootstrapperExtensionCreate(
+    __in HINSTANCE hInstance,
+    __in IBootstrapperExtensionEngine* pEngine,
+    __in const BOOTSTRAPPER_EXTENSION_CREATE_ARGS* pArgs,
+    __out IBootstrapperExtension** ppBootstrapperExtension
+    );
diff --git a/src/ext/NetFx/be/NetfxBundleExtension.h b/src/ext/NetFx/be/NetfxBundleExtension.h
deleted file mode 100644
index 0746dbed..00000000
--- a/src/ext/NetFx/be/NetfxBundleExtension.h
+++ /dev/null
@@ -1,17 +0,0 @@
-#pragma once
-// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
-
-
-// constants
-
-#define NETFX_BUNDLE_EXTENSION_ID BUNDLE_EXTENSION_DECORATION(L"NetfxBundleExtension")
-
-
-// function declarations
-
-HRESULT NetfxBundleExtensionCreate(
-    __in HINSTANCE hInstance,
-    __in IBundleExtensionEngine* pEngine,
-    __in const BUNDLE_EXTENSION_CREATE_ARGS* pArgs,
-    __out IBundleExtension** ppBundleExtension
-    );
diff --git a/src/ext/NetFx/be/detectnetcore.cpp b/src/ext/NetFx/be/detectnetcore.cpp
index 3ed26549..c20cc831 100644
--- a/src/ext/NetFx/be/detectnetcore.cpp
+++ b/src/ext/NetFx/be/detectnetcore.cpp
@@ -45,7 +45,7 @@ LExit:
 HRESULT NetfxPerformDetectNetCore(
     __in LPCWSTR wzVariable,
     __in NETFX_SEARCH* pSearch,
-    __in IBundleExtensionEngine* pEngine,
+    __in IBootstrapperExtensionEngine* pEngine,
     __in LPCWSTR wzBaseDirectory
     )
 {
diff --git a/src/ext/NetFx/be/detectnetcore.h b/src/ext/NetFx/be/detectnetcore.h
index ef93b39b..cd664b57 100644
--- a/src/ext/NetFx/be/detectnetcore.h
+++ b/src/ext/NetFx/be/detectnetcore.h
@@ -4,6 +4,6 @@
 HRESULT NetfxPerformDetectNetCore(
     __in LPCWSTR wzVariable,
     __in NETFX_SEARCH* pSearch,
-    __in IBundleExtensionEngine* pEngine,
+    __in IBootstrapperExtensionEngine* pEngine,
     __in LPCWSTR wzBaseDirectory
     );
diff --git a/src/ext/NetFx/be/detectnetcoresdk.cpp b/src/ext/NetFx/be/detectnetcoresdk.cpp
index 332d8712..03162eea 100644
--- a/src/ext/NetFx/be/detectnetcoresdk.cpp
+++ b/src/ext/NetFx/be/detectnetcoresdk.cpp
@@ -27,7 +27,7 @@ LExit:
 HRESULT NetfxPerformDetectNetCoreSdk(
     __in LPCWSTR wzVariable,
     __in NETFX_SEARCH* pSearch,
-    __in IBundleExtensionEngine* pEngine,
+    __in IBootstrapperExtensionEngine* pEngine,
     __in LPCWSTR wzBaseDirectory
     )
 {
diff --git a/src/ext/NetFx/be/detectnetcoresdk.h b/src/ext/NetFx/be/detectnetcoresdk.h
index 025deaa2..0eef945a 100644
--- a/src/ext/NetFx/be/detectnetcoresdk.h
+++ b/src/ext/NetFx/be/detectnetcoresdk.h
@@ -4,6 +4,6 @@
 HRESULT NetfxPerformDetectNetCoreSdk(
     __in LPCWSTR wzVariable,
     __in NETFX_SEARCH* pSearch,
-    __in IBundleExtensionEngine* pEngine,
+    __in IBootstrapperExtensionEngine* pEngine,
     __in LPCWSTR wzBaseDirectory
     );
diff --git a/src/ext/NetFx/be/detectnetcoresdkfeatureband.cpp b/src/ext/NetFx/be/detectnetcoresdkfeatureband.cpp
index d48c7a85..eca61fad 100644
--- a/src/ext/NetFx/be/detectnetcoresdkfeatureband.cpp
+++ b/src/ext/NetFx/be/detectnetcoresdkfeatureband.cpp
@@ -29,7 +29,7 @@ LExit:
 HRESULT NetfxPerformDetectNetCoreSdkFeatureBand(
     __in LPCWSTR wzVariable,
     __in NETFX_SEARCH* pSearch,
-    __in IBundleExtensionEngine* pEngine,
+    __in IBootstrapperExtensionEngine* pEngine,
     __in LPCWSTR wzBaseDirectory
     )
 {
diff --git a/src/ext/NetFx/be/detectnetcoresdkfeatureband.h b/src/ext/NetFx/be/detectnetcoresdkfeatureband.h
index 1f92cd58..d194c6b7 100644
--- a/src/ext/NetFx/be/detectnetcoresdkfeatureband.h
+++ b/src/ext/NetFx/be/detectnetcoresdkfeatureband.h
@@ -4,6 +4,6 @@
 HRESULT NetfxPerformDetectNetCoreSdkFeatureBand(
     __in LPCWSTR wzVariable,
     __in NETFX_SEARCH* pSearch,
-    __in IBundleExtensionEngine* pEngine,
+    __in IBootstrapperExtensionEngine* pEngine,
     __in LPCWSTR wzBaseDirectory
     );
diff --git a/src/ext/NetFx/be/netfxbe.cpp b/src/ext/NetFx/be/netfxbe.cpp
index 3a34cea3..72eda51a 100644
--- a/src/ext/NetFx/be/netfxbe.cpp
+++ b/src/ext/NetFx/be/netfxbe.cpp
@@ -1,10 +1,10 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
 
 #include "precomp.h"
-#include "BextBaseBundleExtensionProc.h"
+#include "BextBaseBootstrapperExtensionProc.h"
 
 static HINSTANCE vhInstance = NULL;
-static IBundleExtension* vpBundleExtension = NULL;
+static IBootstrapperExtension* vpBootstrapperExtension = NULL;
 
 // function definitions
 
@@ -28,13 +28,13 @@ extern "C" BOOL WINAPI DllMain(
     return TRUE;
 }
 
-extern "C" HRESULT WINAPI BundleExtensionCreate(
-    __in const BUNDLE_EXTENSION_CREATE_ARGS* pArgs,
-    __inout BUNDLE_EXTENSION_CREATE_RESULTS* pResults
+extern "C" HRESULT WINAPI BootstrapperExtensionCreate(
+    __in const BOOTSTRAPPER_EXTENSION_CREATE_ARGS* pArgs,
+    __inout BOOTSTRAPPER_EXTENSION_CREATE_RESULTS* pResults
     )
 {
     HRESULT hr = S_OK;
-    IBundleExtensionEngine* pEngine = NULL;
+    IBootstrapperExtensionEngine* pEngine = NULL;
 
     hr = XmlInitialize();
     ExitOnFailure(hr, "Failed to initialize XML.");
@@ -42,11 +42,11 @@ extern "C" HRESULT WINAPI BundleExtensionCreate(
     hr = BextInitializeFromCreateArgs(pArgs, &pEngine);
     ExitOnFailure(hr, "Failed to initialize bext");
 
-    hr = NetfxBundleExtensionCreate(vhInstance, pEngine, pArgs, &vpBundleExtension);
-    BextExitOnFailure(hr, "Failed to create WixNetfxBundleExtension");
+    hr = NetfxBootstrapperExtensionCreate(vhInstance, pEngine, pArgs, &vpBootstrapperExtension);
+    BextExitOnFailure(hr, "Failed to create WixNetfxBootstrapperExtension");
 
-    pResults->pfnBundleExtensionProc = BextBaseBundleExtensionProc;
-    pResults->pvBundleExtensionProcContext = vpBundleExtension;
+    pResults->pfnBootstrapperExtensionProc = BextBaseBootstrapperExtensionProc;
+    pResults->pvBootstrapperExtensionProcContext = vpBootstrapperExtension;
 
 LExit:
     ReleaseObject(pEngine);
@@ -54,9 +54,9 @@ LExit:
     return hr;
 }
 
-extern "C" void WINAPI BundleExtensionDestroy()
+extern "C" void WINAPI BootstrapperExtensionDestroy()
 {
     BextUninitialize();
-    ReleaseNullObject(vpBundleExtension);
+    ReleaseNullObject(vpBootstrapperExtension);
     XmlUninitialize();
 }
diff --git a/src/ext/NetFx/be/netfxbe.def b/src/ext/NetFx/be/netfxbe.def
index c6605241..2eeaf32c 100644
--- a/src/ext/NetFx/be/netfxbe.def
+++ b/src/ext/NetFx/be/netfxbe.def
@@ -4,5 +4,5 @@
 LIBRARY      "netfxbe"
 
 EXPORTS
-    BundleExtensionCreate
-    BundleExtensionDestroy
+    BootstrapperExtensionCreate
+    BootstrapperExtensionDestroy
diff --git a/src/ext/NetFx/be/netfxbe.vcxproj b/src/ext/NetFx/be/netfxbe.vcxproj
index 94026960..d157b64a 100644
--- a/src/ext/NetFx/be/netfxbe.vcxproj
+++ b/src/ext/NetFx/be/netfxbe.vcxproj
@@ -35,7 +35,7 @@
     <TargetName>netfxbe</TargetName>
     <CharacterSet>Unicode</CharacterSet>
     <ProjectModuleDefinitionFile>netfxbe.def</ProjectModuleDefinitionFile>
-    <Description>WiX Toolset Netfx BundleExtension</Description>
+    <Description>WiX Toolset Netfx BootstrapperExtension</Description>
   </PropertyGroup>
 
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
@@ -50,7 +50,7 @@
     <ClCompile Include="detectnetcoresdk.cpp" />
     <ClCompile Include="detectnetcoresdkfeatureband.cpp" />
     <ClCompile Include="netfxbe.cpp" />
-    <ClCompile Include="NetfxBundleExtension.cpp" />
+    <ClCompile Include="NetfxBootstrapperExtension.cpp" />
     <ClCompile Include="netfxsearch.cpp" />
     <ClCompile Include="precomp.cpp">
       <PrecompiledHeader>Create</PrecompiledHeader>
@@ -62,7 +62,7 @@
     <ClInclude Include="detectnetcore.h" />
     <ClInclude Include="detectnetcoresdk.h" />
     <ClInclude Include="detectnetcoresdkfeatureband.h" />
-    <ClInclude Include="NetfxBundleExtension.h" />
+    <ClInclude Include="NetfxBootstrapperExtension.h" />
     <ClInclude Include="netfxsearch.h" />
     <ClInclude Include="precomp.h" />
     <ClInclude Include="runnetcoresearch.h" />
@@ -73,7 +73,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="WixToolset.BextUtil" />
+    <PackageReference Include="WixToolset.BootstrapperExtensionApi" />
 
     <PackageReference Include="Microsoft.SourceLink.GitHub" PrivateAssets="All" />
   </ItemGroup>
diff --git a/src/ext/NetFx/be/netfxsearch.cpp b/src/ext/NetFx/be/netfxsearch.cpp
index ffbf6ee0..38c34e3c 100644
--- a/src/ext/NetFx/be/netfxsearch.cpp
+++ b/src/ext/NetFx/be/netfxsearch.cpp
@@ -5,7 +5,7 @@
 
 STDMETHODIMP NetfxSearchParseFromXml(
     __in NETFX_SEARCHES* pSearches,
-    __in IXMLDOMNode* pixnBundleExtension
+    __in IXMLDOMNode* pixnBootstrapperExtension
     )
 {
     HRESULT hr = S_OK;
@@ -15,7 +15,7 @@ STDMETHODIMP NetfxSearchParseFromXml(
     BSTR bstrNodeName = NULL;
 
     // Select Netfx search nodes.
-    hr = XmlSelectNodes(pixnBundleExtension, L"NetFxNetCoreSearch|NetFxNetCoreSdkSearch|NetFxNetCoreSdkFeatureBandSearch", &pixnNodes);
+    hr = XmlSelectNodes(pixnBootstrapperExtension, L"NetFxNetCoreSearch|NetFxNetCoreSdkSearch|NetFxNetCoreSdkFeatureBandSearch", &pixnNodes);
     BextExitOnFailure(hr, "Failed to select Netfx search nodes.");
 
     // Get Netfx search node count.
@@ -135,7 +135,7 @@ STDMETHODIMP NetfxSearchExecute(
     __in NETFX_SEARCHES* pSearches,
     __in LPCWSTR wzSearchId,
     __in LPCWSTR wzVariable,
-    __in IBundleExtensionEngine* pEngine,
+    __in IBootstrapperExtensionEngine* pEngine,
     __in LPCWSTR wzBaseDirectory
     )
 {
diff --git a/src/ext/NetFx/be/netfxsearch.h b/src/ext/NetFx/be/netfxsearch.h
index 5793dd55..f532a5a5 100644
--- a/src/ext/NetFx/be/netfxsearch.h
+++ b/src/ext/NetFx/be/netfxsearch.h
@@ -68,7 +68,7 @@ typedef struct _NETFX_SEARCHES
 
 STDMETHODIMP NetfxSearchParseFromXml(
     __in NETFX_SEARCHES* pSearches,
-    __in IXMLDOMNode* pixnBundleExtension
+    __in IXMLDOMNode* pixnBootstrapperExtension
     );
 
 void NetfxSearchUninitialize(
@@ -79,7 +79,7 @@ STDMETHODIMP NetfxSearchExecute(
     __in NETFX_SEARCHES* pSearches,
     __in LPCWSTR wzSearchId,
     __in LPCWSTR wzVariable,
-    __in IBundleExtensionEngine* pEngine,
+    __in IBootstrapperExtensionEngine* pEngine,
     __in LPCWSTR wzBaseDirectory
     );
 
diff --git a/src/ext/NetFx/be/precomp.h b/src/ext/NetFx/be/precomp.h
index a0ae1038..a97b3c5e 100644
--- a/src/ext/NetFx/be/precomp.h
+++ b/src/ext/NetFx/be/precomp.h
@@ -20,12 +20,12 @@
 #include <xmlutil.h>
 
 #include <bextutil.h>
-#include <BextBundleExtensionEngine.h>
+#include <BextBootstrapperExtensionEngine.h>
 
 #include "..\..\beDecor.h"
 #include "netfxsearch.h"
 #include "detectnetcore.h"
 #include "detectnetcoresdk.h"
 #include "detectnetcoresdkfeatureband.h"
-#include "NetfxBundleExtension.h"
+#include "NetfxBootstrapperExtension.h"
 #include "runnetcoresearch.h"
diff --git a/src/ext/NetFx/wixext/NetFxCompiler.cs b/src/ext/NetFx/wixext/NetFxCompiler.cs
index bfadbe07..70e83cc9 100644
--- a/src/ext/NetFx/wixext/NetFxCompiler.cs
+++ b/src/ext/NetFx/wixext/NetFxCompiler.cs
@@ -225,15 +225,15 @@ namespace WixToolset.Netfx
 
             this.ParseHelper.ParseForExtensionElements(this.Context.Extensions, intermediate, section, element);
 
-            var bundleExtensionId = this.ParseHelper.CreateIdentifierValueFromPlatform("Wix4NetfxBundleExtension", this.Context.Platform, BurnPlatforms.X86 | BurnPlatforms.X64 | BurnPlatforms.ARM64);
-            if (bundleExtensionId == null)
+            var bootstrapperExtensionId = this.ParseHelper.CreateIdentifierValueFromPlatform("Wix4NetfxBootstrapperExtension", this.Context.Platform, BurnPlatforms.X86 | BurnPlatforms.X64 | BurnPlatforms.ARM64);
+            if (bootstrapperExtensionId == null)
             {
                 this.Messaging.Write(ErrorMessages.UnsupportedPlatformForElement(sourceLineNumbers, this.Context.Platform.ToString(), element.Name.LocalName));
             }
 
             if (!this.Messaging.EncounteredError)
             {
-                this.ParseHelper.CreateWixSearchSymbol(section, sourceLineNumbers, element.Name.LocalName, id, variable, condition, after, bundleExtensionId);
+                this.ParseHelper.CreateWixSearchSymbol(section, sourceLineNumbers, element.Name.LocalName, id, variable, condition, after, bootstrapperExtensionId);
 
                 section.AddSymbol(new NetFxNetCoreSearchSymbol(sourceLineNumbers, id)
                 {
@@ -354,15 +354,15 @@ namespace WixToolset.Netfx
 
             this.ParseHelper.ParseForExtensionElements(this.Context.Extensions, intermediate, section, element);
 
-            var bundleExtensionId = this.ParseHelper.CreateIdentifierValueFromPlatform("Wix4NetfxBundleExtension", this.Context.Platform, BurnPlatforms.X86 | BurnPlatforms.X64 | BurnPlatforms.ARM64);
-            if (bundleExtensionId == null)
+            var bootstrapperExtensionId = this.ParseHelper.CreateIdentifierValueFromPlatform("Wix4NetfxBootstrapperExtension", this.Context.Platform, BurnPlatforms.X86 | BurnPlatforms.X64 | BurnPlatforms.ARM64);
+            if (bootstrapperExtensionId == null)
             {
                 this.Messaging.Write(ErrorMessages.UnsupportedPlatformForElement(sourceLineNumbers, this.Context.Platform.ToString(), element.Name.LocalName));
             }
 
             if (!this.Messaging.EncounteredError)
             {
-                this.ParseHelper.CreateWixSearchSymbol(section, sourceLineNumbers, element.Name.LocalName, id, variable, condition, after, bundleExtensionId);
+                this.ParseHelper.CreateWixSearchSymbol(section, sourceLineNumbers, element.Name.LocalName, id, variable, condition, after, bootstrapperExtensionId);
 
                 section.AddSymbol(new NetFxNetCoreSdkSearchSymbol(sourceLineNumbers, id)
                 {
@@ -503,15 +503,15 @@ namespace WixToolset.Netfx
 
             this.ParseHelper.ParseForExtensionElements(this.Context.Extensions, intermediate, section, element);
 
-            var bundleExtensionId = this.ParseHelper.CreateIdentifierValueFromPlatform("Wix4NetfxBundleExtension", this.Context.Platform, BurnPlatforms.X86 | BurnPlatforms.X64 | BurnPlatforms.ARM64);
-            if (bundleExtensionId == null)
+            var bootstrapperExtensionId = this.ParseHelper.CreateIdentifierValueFromPlatform("Wix4NetfxBootstrapperExtension", this.Context.Platform, BurnPlatforms.X86 | BurnPlatforms.X64 | BurnPlatforms.ARM64);
+            if (bootstrapperExtensionId == null)
             {
                 this.Messaging.Write(ErrorMessages.UnsupportedPlatformForElement(sourceLineNumbers, this.Context.Platform.ToString(), element.Name.LocalName));
             }
 
             if (!this.Messaging.EncounteredError)
             {
-                this.ParseHelper.CreateWixSearchSymbol(section, sourceLineNumbers, element.Name.LocalName, id, variable, condition, after, bundleExtensionId);
+                this.ParseHelper.CreateWixSearchSymbol(section, sourceLineNumbers, element.Name.LocalName, id, variable, condition, after, bootstrapperExtensionId);
 
                 section.AddSymbol(new NetFxNetCoreSdkFeatureBandSearchSymbol(sourceLineNumbers, id)
                 {
diff --git a/src/ext/NetFx/wixext/Symbols/NetfxSymbolDefinitions.cs b/src/ext/NetFx/wixext/Symbols/NetfxSymbolDefinitions.cs
index 6371a951..cc25a3eb 100644
--- a/src/ext/NetFx/wixext/Symbols/NetfxSymbolDefinitions.cs
+++ b/src/ext/NetFx/wixext/Symbols/NetfxSymbolDefinitions.cs
@@ -53,9 +53,9 @@ namespace WixToolset.Netfx
 
         static NetfxSymbolDefinitions()
         {
-            NetFxNetCoreSearch.AddTag(BurnConstants.BundleExtensionSearchSymbolDefinitionTag);
-            NetFxNetCoreSdkSearch.AddTag(BurnConstants.BundleExtensionSearchSymbolDefinitionTag);
-            NetFxNetCoreSdkFeatureBandSearch.AddTag(BurnConstants.BundleExtensionSearchSymbolDefinitionTag);
+            NetFxNetCoreSearch.AddTag(BurnConstants.BootstrapperExtensionSearchSymbolDefinitionTag);
+            NetFxNetCoreSdkSearch.AddTag(BurnConstants.BootstrapperExtensionSearchSymbolDefinitionTag);
+            NetFxNetCoreSdkFeatureBandSearch.AddTag(BurnConstants.BootstrapperExtensionSearchSymbolDefinitionTag);
         }
     }
 }
diff --git a/src/ext/NetFx/wixlib/NetfxBundleExtension_Platform.wxi b/src/ext/NetFx/wixlib/NetfxBootstrapperExtension_Platform.wxi
index bc332efc..98fbd523 100644
--- a/src/ext/NetFx/wixlib/NetfxBundleExtension_Platform.wxi
+++ b/src/ext/NetFx/wixlib/NetfxBootstrapperExtension_Platform.wxi
@@ -5,11 +5,11 @@
     <?include ..\..\caDecor.wxi ?>
 
     <Fragment>
-        <BundleExtension Id="$(var.Prefix)NetfxBundleExtension$(var.Suffix)" SourceFile="!(bindpath.netfxbe.$(var.platform))netfxbe.dll" Name="$(var.Prefix)NetfxBundleExtension$(var.Suffix)\netfxbe.dll">
+        <BootstrapperExtension Id="$(var.Prefix)NetfxBootstrapperExtension$(var.Suffix)" SourceFile="!(bindpath.netfxbe.$(var.platform))netfxbe.dll" Name="$(var.Prefix)NetfxBootstrapperExtension$(var.Suffix)\netfxbe.dll">
             <?foreach PLATFORM in x86;x64;arm64?>
-            <Payload SourceFile="!(bindpath.netcoresearch.$(var.PLATFORM))netcoresearch.exe" Name="$(var.Prefix)NetfxBundleExtension$(var.Suffix)\$(var.PLATFORM)\netcoresearch.exe" />
-            <Payload SourceFile="!(bindpath.netcoresearch.$(var.PLATFORM))hostfxr.dll" Name="$(var.Prefix)NetfxBundleExtension$(var.Suffix)\$(var.PLATFORM)\hostfxr.dll" />
+            <Payload SourceFile="!(bindpath.netcoresearch.$(var.PLATFORM))netcoresearch.exe" Name="$(var.Prefix)NetfxBootstrapperExtension$(var.Suffix)\$(var.PLATFORM)\netcoresearch.exe" />
+            <Payload SourceFile="!(bindpath.netcoresearch.$(var.PLATFORM))hostfxr.dll" Name="$(var.Prefix)NetfxBootstrapperExtension$(var.Suffix)\$(var.PLATFORM)\hostfxr.dll" />
             <?endforeach?>
-        </BundleExtension>
+        </BootstrapperExtension>
     </Fragment>
 </Include>
diff --git a/src/ext/NetFx/wixlib/NetfxBundleExtension_arm64.wxs b/src/ext/NetFx/wixlib/NetfxBootstrapperExtension_arm64.wxs
index 13757dd8..00b607a1 100644
--- a/src/ext/NetFx/wixlib/NetfxBundleExtension_arm64.wxs
+++ b/src/ext/NetFx/wixlib/NetfxBootstrapperExtension_arm64.wxs
@@ -3,5 +3,5 @@
 
 <Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
     <?define platform=arm64 ?>
-    <?include NetfxBundleExtension_Platform.wxi ?>
+    <?include NetfxBootstrapperExtension_Platform.wxi ?>
 </Wix>
diff --git a/src/ext/Util/wixlib/UtilBundleExtension_x64.wxs b/src/ext/NetFx/wixlib/NetfxBootstrapperExtension_x64.wxs
index 96c85a5b..a7412e60 100644
--- a/src/ext/Util/wixlib/UtilBundleExtension_x64.wxs
+++ b/src/ext/NetFx/wixlib/NetfxBootstrapperExtension_x64.wxs
@@ -3,5 +3,5 @@
 
 <Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
     <?define platform=x64 ?>
-    <?include UtilBundleExtension_Platform.wxi ?>
+    <?include NetfxBootstrapperExtension_Platform.wxi ?>
 </Wix>
diff --git a/src/ext/NetFx/wixlib/NetfxBundleExtension_x86.wxs b/src/ext/NetFx/wixlib/NetfxBootstrapperExtension_x86.wxs
index 76a8358f..406f6139 100644
--- a/src/ext/NetFx/wixlib/NetfxBundleExtension_x86.wxs
+++ b/src/ext/NetFx/wixlib/NetfxBootstrapperExtension_x86.wxs
@@ -3,5 +3,5 @@
 
 <Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
     <?define platform=x86 ?>
-    <?include NetfxBundleExtension_Platform.wxi ?>
+    <?include NetfxBootstrapperExtension_Platform.wxi ?>
 </Wix>
diff --git a/src/ext/Util/be/UtilBootstrapperExtension.cpp b/src/ext/Util/be/UtilBootstrapperExtension.cpp
new file mode 100644
index 00000000..4d4d89c7
--- /dev/null
+++ b/src/ext/Util/be/UtilBootstrapperExtension.cpp
@@ -0,0 +1,87 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+#include "precomp.h"
+#include "BextBaseBootstrapperExtension.h"
+
+class CWixUtilBootstrapperExtension : public CBextBaseBootstrapperExtension
+{
+public: // IBootstrapperExtension
+    virtual STDMETHODIMP Search(
+        __in LPCWSTR wzId,
+        __in LPCWSTR wzVariable
+        )
+    {
+        HRESULT hr = S_OK;
+
+        hr = UtilSearchExecute(&m_searches, wzId, wzVariable, m_pEngine);
+
+        return hr;
+    }
+
+public: //CBextBaseBootstrapperExtension
+    virtual STDMETHODIMP Initialize(
+        __in const BOOTSTRAPPER_EXTENSION_CREATE_ARGS* pCreateArgs
+        )
+    {
+        HRESULT hr = S_OK;
+        IXMLDOMDocument* pixdManifest = NULL;
+        IXMLDOMNode* pixnBootstrapperExtension = NULL;
+
+        hr = __super::Initialize(pCreateArgs);
+        BextExitOnFailure(hr, "CBextBaseBootstrapperExtension initialization failed.");
+
+        hr = XmlLoadDocumentFromFile(m_sczBootstrapperExtensionDataPath, &pixdManifest);
+        BextExitOnFailure(hr, "Failed to load bundle extension manifest from path: %ls", m_sczBootstrapperExtensionDataPath);
+
+        hr = BextGetBootstrapperExtensionDataNode(pixdManifest, UTIL_BOOTSTRAPPER_EXTENSION_ID, &pixnBootstrapperExtension);
+        BextExitOnFailure(hr, "Failed to get BootstrapperExtension '%ls'", UTIL_BOOTSTRAPPER_EXTENSION_ID);
+
+        hr = UtilSearchParseFromXml(&m_searches, pixnBootstrapperExtension);
+        BextExitOnFailure(hr, "Failed to parse searches from bundle extension manifest.");
+
+    LExit:
+        ReleaseObject(pixnBootstrapperExtension);
+        ReleaseObject(pixdManifest);
+
+        return hr;
+    }
+
+public:
+    CWixUtilBootstrapperExtension(
+        __in IBootstrapperExtensionEngine* pEngine
+        ) : CBextBaseBootstrapperExtension(pEngine)
+    {
+        m_searches = { };
+    }
+
+    ~CWixUtilBootstrapperExtension()
+    {
+        UtilSearchUninitialize(&m_searches);
+    }
+
+private:
+    UTIL_SEARCHES m_searches;
+};
+
+HRESULT UtilBootstrapperExtensionCreate(
+    __in IBootstrapperExtensionEngine* pEngine,
+    __in const BOOTSTRAPPER_EXTENSION_CREATE_ARGS* pArgs,
+    __out IBootstrapperExtension** ppBootstrapperExtension
+    )
+{
+    HRESULT hr = S_OK;
+    CWixUtilBootstrapperExtension* pExtension = NULL;
+
+    pExtension = new CWixUtilBootstrapperExtension(pEngine);
+    BextExitOnNull(pExtension, hr, E_OUTOFMEMORY, "Failed to create new CWixUtilBootstrapperExtension.");
+
+    hr = pExtension->Initialize(pArgs);
+    BextExitOnFailure(hr, "CWixUtilBootstrapperExtension initialization failed.");
+
+    *ppBootstrapperExtension = pExtension;
+    pExtension = NULL;
+
+LExit:
+    ReleaseObject(pExtension);
+    return hr;
+}
diff --git a/src/ext/Util/be/UtilBootstrapperExtension.h b/src/ext/Util/be/UtilBootstrapperExtension.h
new file mode 100644
index 00000000..32cabb89
--- /dev/null
+++ b/src/ext/Util/be/UtilBootstrapperExtension.h
@@ -0,0 +1,16 @@
+#pragma once
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+
+// constants
+
+#define UTIL_BOOTSTRAPPER_EXTENSION_ID BOOTSTRAPPER_EXTENSION_DECORATION(L"UtilBootstrapperExtension")
+
+
+// function declarations
+
+HRESULT UtilBootstrapperExtensionCreate(
+    __in IBootstrapperExtensionEngine* pEngine,
+    __in const BOOTSTRAPPER_EXTENSION_CREATE_ARGS* pArgs,
+    __out IBootstrapperExtension** ppBootstrapperExtension
+    );
diff --git a/src/ext/Util/be/UtilBundleExtension.cpp b/src/ext/Util/be/UtilBundleExtension.cpp
deleted file mode 100644
index 23f5d94f..00000000
--- a/src/ext/Util/be/UtilBundleExtension.cpp
+++ /dev/null
@@ -1,87 +0,0 @@
-// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
-
-#include "precomp.h"
-#include "BextBaseBundleExtension.h"
-
-class CWixUtilBundleExtension : public CBextBaseBundleExtension
-{
-public: // IBundleExtension
-    virtual STDMETHODIMP Search(
-        __in LPCWSTR wzId,
-        __in LPCWSTR wzVariable
-        )
-    {
-        HRESULT hr = S_OK;
-
-        hr = UtilSearchExecute(&m_searches, wzId, wzVariable, m_pEngine);
-
-        return hr;
-    }
-
-public: //CBextBaseBundleExtension
-    virtual STDMETHODIMP Initialize(
-        __in const BUNDLE_EXTENSION_CREATE_ARGS* pCreateArgs
-        )
-    {
-        HRESULT hr = S_OK;
-        IXMLDOMDocument* pixdManifest = NULL;
-        IXMLDOMNode* pixnBundleExtension = NULL;
-
-        hr = __super::Initialize(pCreateArgs);
-        BextExitOnFailure(hr, "CBextBaseBundleExtension initialization failed.");
-
-        hr = XmlLoadDocumentFromFile(m_sczBundleExtensionDataPath, &pixdManifest);
-        BextExitOnFailure(hr, "Failed to load bundle extension manifest from path: %ls", m_sczBundleExtensionDataPath);
-
-        hr = BextGetBundleExtensionDataNode(pixdManifest, UTIL_BUNDLE_EXTENSION_ID, &pixnBundleExtension);
-        BextExitOnFailure(hr, "Failed to get BundleExtension '%ls'", UTIL_BUNDLE_EXTENSION_ID);
-
-        hr = UtilSearchParseFromXml(&m_searches, pixnBundleExtension);
-        BextExitOnFailure(hr, "Failed to parse searches from bundle extension manifest.");
-
-    LExit:
-        ReleaseObject(pixnBundleExtension);
-        ReleaseObject(pixdManifest);
-
-        return hr;
-    }
-
-public:
-    CWixUtilBundleExtension(
-        __in IBundleExtensionEngine* pEngine
-        ) : CBextBaseBundleExtension(pEngine)
-    {
-        m_searches = { };
-    }
-
-    ~CWixUtilBundleExtension()
-    {
-        UtilSearchUninitialize(&m_searches);
-    }
-
-private:
-    UTIL_SEARCHES m_searches;
-};
-
-HRESULT UtilBundleExtensionCreate(
-    __in IBundleExtensionEngine* pEngine,
-    __in const BUNDLE_EXTENSION_CREATE_ARGS* pArgs,
-    __out IBundleExtension** ppBundleExtension
-    )
-{
-    HRESULT hr = S_OK;
-    CWixUtilBundleExtension* pExtension = NULL;
-
-    pExtension = new CWixUtilBundleExtension(pEngine);
-    BextExitOnNull(pExtension, hr, E_OUTOFMEMORY, "Failed to create new CWixUtilBundleExtension.");
-
-    hr = pExtension->Initialize(pArgs);
-    BextExitOnFailure(hr, "CWixUtilBundleExtension initialization failed.");
-
-    *ppBundleExtension = pExtension;
-    pExtension = NULL;
-
-LExit:
-    ReleaseObject(pExtension);
-    return hr;
-}
diff --git a/src/ext/Util/be/UtilBundleExtension.h b/src/ext/Util/be/UtilBundleExtension.h
deleted file mode 100644
index c55d6b85..00000000
--- a/src/ext/Util/be/UtilBundleExtension.h
+++ /dev/null
@@ -1,16 +0,0 @@
-#pragma once
-// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
-
-
-// constants
-
-#define UTIL_BUNDLE_EXTENSION_ID BUNDLE_EXTENSION_DECORATION(L"UtilBundleExtension")
-
-
-// function declarations
-
-HRESULT UtilBundleExtensionCreate(
-    __in IBundleExtensionEngine* pEngine,
-    __in const BUNDLE_EXTENSION_CREATE_ARGS* pArgs,
-    __out IBundleExtension** ppBundleExtension
-    );
diff --git a/src/ext/Util/be/detectsha2support.cpp b/src/ext/Util/be/detectsha2support.cpp
index 4abfc63c..c7175a47 100644
--- a/src/ext/Util/be/detectsha2support.cpp
+++ b/src/ext/Util/be/detectsha2support.cpp
@@ -41,7 +41,7 @@ LExit:
 HRESULT UtilPerformDetectSHA2CodeSigning(
     __in LPCWSTR wzVariable,
     __in UTIL_SEARCH* /*pSearch*/,
-    __in IBundleExtensionEngine* pEngine
+    __in IBootstrapperExtensionEngine* pEngine
     )
 {
     HRESULT hr = S_OK;
diff --git a/src/ext/Util/be/detectsha2support.h b/src/ext/Util/be/detectsha2support.h
index c38a3d59..b387a3ea 100644
--- a/src/ext/Util/be/detectsha2support.h
+++ b/src/ext/Util/be/detectsha2support.h
@@ -4,5 +4,5 @@
 HRESULT UtilPerformDetectSHA2CodeSigning(
     __in LPCWSTR wzVariable,
     __in UTIL_SEARCH* pSearch,
-    __in IBundleExtensionEngine* pEngine
-    );
\ No newline at end of file
+    __in IBootstrapperExtensionEngine* pEngine
+    );
diff --git a/src/ext/Util/be/precomp.h b/src/ext/Util/be/precomp.h
index d04bf305..0cf0c761 100644
--- a/src/ext/Util/be/precomp.h
+++ b/src/ext/Util/be/precomp.h
@@ -24,9 +24,9 @@
 #include <xmlutil.h>
 
 #include <bextutil.h>
-#include <BextBundleExtensionEngine.h>
+#include <BextBootstrapperExtensionEngine.h>
 
 #include "..\..\beDecor.h"
 #include "utilsearch.h"
 #include "detectsha2support.h"
-#include "UtilBundleExtension.h"
+#include "UtilBootstrapperExtension.h"
diff --git a/src/ext/Util/be/utilbe.cpp b/src/ext/Util/be/utilbe.cpp
index d9816dc7..b4e6fda3 100644
--- a/src/ext/Util/be/utilbe.cpp
+++ b/src/ext/Util/be/utilbe.cpp
@@ -1,19 +1,19 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
 
 #include "precomp.h"
-#include "BextBaseBundleExtensionProc.h"
+#include "BextBaseBootstrapperExtensionProc.h"
 
-static IBundleExtension* vpBundleExtension = NULL;
+static IBootstrapperExtension* vpBootstrapperExtension = NULL;
 
 // function definitions
 
-extern "C" HRESULT WINAPI BundleExtensionCreate(
-    __in const BUNDLE_EXTENSION_CREATE_ARGS* pArgs,
-    __inout BUNDLE_EXTENSION_CREATE_RESULTS* pResults
+extern "C" HRESULT WINAPI BootstrapperExtensionCreate(
+    __in const BOOTSTRAPPER_EXTENSION_CREATE_ARGS* pArgs,
+    __inout BOOTSTRAPPER_EXTENSION_CREATE_RESULTS* pResults
     )
 {
     HRESULT hr = S_OK;
-    IBundleExtensionEngine* pEngine = NULL;
+    IBootstrapperExtensionEngine* pEngine = NULL;
 
     hr = XmlInitialize();
     ExitOnFailure(hr, "Failed to initialize XML.");
@@ -21,11 +21,11 @@ extern "C" HRESULT WINAPI BundleExtensionCreate(
     hr = BextInitializeFromCreateArgs(pArgs, &pEngine);
     ExitOnFailure(hr, "Failed to initialize bext");
 
-    hr = UtilBundleExtensionCreate(pEngine, pArgs, &vpBundleExtension);
-    BextExitOnFailure(hr, "Failed to create WixUtilBundleExtension");
+    hr = UtilBootstrapperExtensionCreate(pEngine, pArgs, &vpBootstrapperExtension);
+    BextExitOnFailure(hr, "Failed to create WixUtilBootstrapperExtension");
 
-    pResults->pfnBundleExtensionProc = BextBaseBundleExtensionProc;
-    pResults->pvBundleExtensionProcContext = vpBundleExtension;
+    pResults->pfnBootstrapperExtensionProc = BextBaseBootstrapperExtensionProc;
+    pResults->pvBootstrapperExtensionProcContext = vpBootstrapperExtension;
 
 LExit:
     ReleaseObject(pEngine);
@@ -33,9 +33,9 @@ LExit:
     return hr;
 }
 
-extern "C" void WINAPI BundleExtensionDestroy()
+extern "C" void WINAPI BootstrapperExtensionDestroy()
 {
     BextUninitialize();
-    ReleaseNullObject(vpBundleExtension);
+    ReleaseNullObject(vpBootstrapperExtension);
     XmlUninitialize();
-}
\ No newline at end of file
+}
diff --git a/src/ext/Util/be/utilbe.def b/src/ext/Util/be/utilbe.def
index 711b1a5c..b4e7e893 100644
--- a/src/ext/Util/be/utilbe.def
+++ b/src/ext/Util/be/utilbe.def
@@ -4,5 +4,5 @@
 LIBRARY      "utilbe"
 
 EXPORTS
-    BundleExtensionCreate
-    BundleExtensionDestroy
+    BootstrapperExtensionCreate
+    BootstrapperExtensionDestroy
diff --git a/src/ext/Util/be/utilbe.vcxproj b/src/ext/Util/be/utilbe.vcxproj
index d2697bbd..df06cb46 100644
--- a/src/ext/Util/be/utilbe.vcxproj
+++ b/src/ext/Util/be/utilbe.vcxproj
@@ -35,7 +35,7 @@
     <TargetName>utilbe</TargetName>
     <CharacterSet>Unicode</CharacterSet>
     <ProjectModuleDefinitionFile>utilbe.def</ProjectModuleDefinitionFile>
-    <Description>WiX Toolset Util BundleExtension</Description>
+    <Description>WiX Toolset Util BootstrapperExtension</Description>
   </PropertyGroup>
 
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
@@ -51,14 +51,14 @@
       <PrecompiledHeader>Create</PrecompiledHeader>
     </ClCompile>
     <ClCompile Include="utilbe.cpp" />
-    <ClCompile Include="UtilBundleExtension.cpp" />
+    <ClCompile Include="UtilBootstrapperExtension.cpp" />
     <ClCompile Include="utilsearch.cpp" />
   </ItemGroup>
 
   <ItemGroup>
     <ClInclude Include="detectsha2support.h" />
     <ClInclude Include="precomp.h" />
-    <ClInclude Include="UtilBundleExtension.h" />
+    <ClInclude Include="UtilBootstrapperExtension.h" />
     <ClInclude Include="utilsearch.h" />
   </ItemGroup>
 
@@ -67,7 +67,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="WixToolset.BextUtil" />
+    <PackageReference Include="WixToolset.BootstrapperExtensionApi" />
 
     <PackageReference Include="Microsoft.SourceLink.GitHub" PrivateAssets="All" />
   </ItemGroup>
diff --git a/src/ext/Util/be/utilsearch.cpp b/src/ext/Util/be/utilsearch.cpp
index 20a514d8..59c497e3 100644
--- a/src/ext/Util/be/utilsearch.cpp
+++ b/src/ext/Util/be/utilsearch.cpp
@@ -5,7 +5,7 @@
 
 STDMETHODIMP UtilSearchParseFromXml(
     __in UTIL_SEARCHES* pSearches,
-    __in IXMLDOMNode* pixnBundleExtension
+    __in IXMLDOMNode* pixnBootstrapperExtension
     )
 {
     HRESULT hr = S_OK;
@@ -16,7 +16,7 @@ STDMETHODIMP UtilSearchParseFromXml(
     LPWSTR scz = NULL;
 
     // Select Util search nodes.
-    hr = XmlSelectNodes(pixnBundleExtension, L"WixWindowsFeatureSearch", &pixnNodes);
+    hr = XmlSelectNodes(pixnBootstrapperExtension, L"WixWindowsFeatureSearch", &pixnNodes);
     BextExitOnFailure(hr, "Failed to select Util search nodes.");
 
     // Get Util search node count.
@@ -103,7 +103,7 @@ STDMETHODIMP UtilSearchExecute(
     __in UTIL_SEARCHES* pSearches,
     __in LPCWSTR wzSearchId,
     __in LPCWSTR wzVariable,
-    __in IBundleExtensionEngine* pEngine
+    __in IBootstrapperExtensionEngine* pEngine
     )
 {
     HRESULT hr = S_OK;
diff --git a/src/ext/Util/be/utilsearch.h b/src/ext/Util/be/utilsearch.h
index deeab1f7..d19e240f 100644
--- a/src/ext/Util/be/utilsearch.h
+++ b/src/ext/Util/be/utilsearch.h
@@ -44,7 +44,7 @@ typedef struct _UTIL_SEARCHES
 
 STDMETHODIMP UtilSearchParseFromXml(
     __in UTIL_SEARCHES* pSearches,
-    __in IXMLDOMNode* pixnBundleExtension
+    __in IXMLDOMNode* pixnBootstrapperExtension
     );
 
 void UtilSearchUninitialize(
@@ -55,7 +55,7 @@ STDMETHODIMP UtilSearchExecute(
     __in UTIL_SEARCHES* pSearches,
     __in LPCWSTR wzSearchId,
     __in LPCWSTR wzVariable,
-    __in IBundleExtensionEngine* pEngine
+    __in IBootstrapperExtensionEngine* pEngine
     );
 
 STDMETHODIMP UtilSearchFindById(
diff --git a/src/ext/Util/test/WixToolsetTest.Util/UtilExtensionFixture.cs b/src/ext/Util/test/WixToolsetTest.Util/UtilExtensionFixture.cs
index 06e70dcf..0a93f3a4 100644
--- a/src/ext/Util/test/WixToolsetTest.Util/UtilExtensionFixture.cs
+++ b/src/ext/Util/test/WixToolsetTest.Util/UtilExtensionFixture.cs
@@ -372,11 +372,11 @@ namespace WixToolsetTest.Util
                 var extractResult = BundleExtractor.ExtractBAContainer(null, bundlePath, baFolderPath, extractFolderPath);
                 extractResult.AssertSuccess();
 
-                var bundleExtensionDatas = extractResult.SelectBundleExtensionDataNodes("/be:BundleExtensionData/be:BundleExtension[@Id='Wix4UtilBundleExtension_X86']");
-                Assert.Equal(1, bundleExtensionDatas.Count);
-                Assert.Equal("<BundleExtension Id='Wix4UtilBundleExtension_X86'>" +
+                var bootstrapperExtensionDatas = extractResult.SelectBootstrapperExtensionDataNodes("/be:BootstrapperExtensionData/be:BootstrapperExtension[@Id='Wix4UtilBootstrapperExtension_X86']");
+                Assert.Equal(1, bootstrapperExtensionDatas.Count);
+                Assert.Equal("<BootstrapperExtension Id='Wix4UtilBootstrapperExtension_X86'>" +
                     "<WixWindowsFeatureSearch Id='DetectSHA2SupportId' Type='sha2CodeSigning' />" +
-                    "</BundleExtension>", bundleExtensionDatas[0].GetTestXml());
+                    "</BootstrapperExtension>", bootstrapperExtensionDatas[0].GetTestXml());
 
                 var utilSearches = extractResult.SelectManifestNodes("/burn:BurnManifest/*[self::burn:ExtensionSearch or self::burn:DirectorySearch or self::burn:FileSearch or self::burn:MsiProductSearch or self::burn:RegistrySearch]")
                                                 .Cast<XmlElement>()
@@ -384,7 +384,7 @@ namespace WixToolsetTest.Util
                                                 .ToArray();
                 WixAssert.CompareLineByLine(new[]
                 {
-                    @"<ExtensionSearch Id='DetectSHA2SupportId' Variable='IsSHA2Supported' ExtensionId='Wix4UtilBundleExtension_X86' />",
+                    @"<ExtensionSearch Id='DetectSHA2SupportId' Variable='IsSHA2Supported' ExtensionId='Wix4UtilBootstrapperExtension_X86' />",
                     @"<DirectorySearch Id='DirectorySearchId' Variable='DirectorySearchVariable' Path='%windir%\System32' Type='exists' DisableFileRedirection='yes' />",
                     @"<FileSearch Id='FileSearchId' Variable='FileSearchVariable' Path='%windir%\System32\mscoree.dll' Type='exists' />",
                     @"<MsiProductSearch Id='ProductSearchId' Variable='ProductSearchVariable' Condition='1 &amp; 2 &lt; 3' UpgradeCode='{738D02BF-E231-4370-8209-E9FD4E1BE2A1}' Type='version' />",
diff --git a/src/ext/Util/wixext/Symbols/UtilSymbolDefinitions.cs b/src/ext/Util/wixext/Symbols/UtilSymbolDefinitions.cs
index 3b357a96..8152868f 100644
--- a/src/ext/Util/wixext/Symbols/UtilSymbolDefinitions.cs
+++ b/src/ext/Util/wixext/Symbols/UtilSymbolDefinitions.cs
@@ -94,7 +94,7 @@ namespace WixToolset.Util
 
                 case UtilSymbolDefinitionType.WixRemoveRegistryKeyEx:
                     return UtilSymbolDefinitions.WixRemoveRegistryKeyEx;
-                    
+
                 case UtilSymbolDefinitionType.WixRestartResource:
                     return UtilSymbolDefinitions.WixRestartResource;
 
@@ -117,7 +117,7 @@ namespace WixToolset.Util
 
         static UtilSymbolDefinitions()
         {
-            WixWindowsFeatureSearch.AddTag(BurnConstants.BundleExtensionSearchSymbolDefinitionTag);
+            WixWindowsFeatureSearch.AddTag(BurnConstants.BootstrapperExtensionSearchSymbolDefinitionTag);
         }
     }
 }
diff --git a/src/ext/Util/wixext/UtilCompiler.cs b/src/ext/Util/wixext/UtilCompiler.cs
index 6221c052..3bcd2c0b 100644
--- a/src/ext/Util/wixext/UtilCompiler.cs
+++ b/src/ext/Util/wixext/UtilCompiler.cs
@@ -611,15 +611,15 @@ namespace WixToolset.Util
 
             this.ParseHelper.ParseForExtensionElements(this.Context.Extensions, intermediate, section, element);
 
-            var bundleExtensionId = this.ParseHelper.CreateIdentifierValueFromPlatform("Wix4UtilBundleExtension", this.Context.Platform, BurnPlatforms.X86 | BurnPlatforms.X64 | BurnPlatforms.ARM64);
-            if (bundleExtensionId == null)
+            var bootstrapperExtensionId = this.ParseHelper.CreateIdentifierValueFromPlatform("Wix4UtilBootstrapperExtension", this.Context.Platform, BurnPlatforms.X86 | BurnPlatforms.X64 | BurnPlatforms.ARM64);
+            if (bootstrapperExtensionId == null)
             {
                 this.Messaging.Write(ErrorMessages.UnsupportedPlatformForElement(sourceLineNumbers, this.Context.Platform.ToString(), element.Name.LocalName));
             }
 
             if (!this.Messaging.EncounteredError)
             {
-                this.ParseHelper.CreateWixSearchSymbol(section, sourceLineNumbers, element.Name.LocalName, id, variable, condition, after, bundleExtensionId);
+                this.ParseHelper.CreateWixSearchSymbol(section, sourceLineNumbers, element.Name.LocalName, id, variable, condition, after, bootstrapperExtensionId);
 
                 section.AddSymbol(new WixWindowsFeatureSearchSymbol(sourceLineNumbers, id)
                 {
diff --git a/src/ext/Util/wixlib/UtilBundleExtension_Platform.wxi b/src/ext/Util/wixlib/UtilBootstrapperExtension_Platform.wxi
index 5c964d7d..cbaf3f56 100644
--- a/src/ext/Util/wixlib/UtilBundleExtension_Platform.wxi
+++ b/src/ext/Util/wixlib/UtilBootstrapperExtension_Platform.wxi
@@ -5,6 +5,6 @@
     <?include ..\..\caDecor.wxi ?>
 
     <Fragment>
-        <BundleExtension Id="$(var.Prefix)UtilBundleExtension$(var.Suffix)" SourceFile="!(bindpath.utilbe.$(var.platform))utilbe.dll" Name="$(var.Prefix)UtilBundleExtension$(var.Suffix)\utilbe.dll" />
+        <BootstrapperExtension Id="$(var.Prefix)UtilBootstrapperExtension$(var.Suffix)" SourceFile="!(bindpath.utilbe.$(var.platform))utilbe.dll" Name="$(var.Prefix)UtilBootstrapperExtension$(var.Suffix)\utilbe.dll" />
     </Fragment>
 </Include>
diff --git a/src/ext/Util/wixlib/UtilBundleExtension_arm64.wxs b/src/ext/Util/wixlib/UtilBootstrapperExtension_arm64.wxs
index b17be031..093de00d 100644
--- a/src/ext/Util/wixlib/UtilBundleExtension_arm64.wxs
+++ b/src/ext/Util/wixlib/UtilBootstrapperExtension_arm64.wxs
@@ -3,5 +3,5 @@
 
 <Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
     <?define platform=arm64 ?>
-    <?include UtilBundleExtension_Platform.wxi ?>
+    <?include UtilBootstrapperExtension_Platform.wxi ?>
 </Wix>
diff --git a/src/ext/NetFx/wixlib/NetfxBundleExtension_x64.wxs b/src/ext/Util/wixlib/UtilBootstrapperExtension_x64.wxs
index f6c27a8e..e778fc42 100644
--- a/src/ext/NetFx/wixlib/NetfxBundleExtension_x64.wxs
+++ b/src/ext/Util/wixlib/UtilBootstrapperExtension_x64.wxs
@@ -3,5 +3,5 @@
 
 <Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
     <?define platform=x64 ?>
-    <?include NetfxBundleExtension_Platform.wxi ?>
+    <?include UtilBootstrapperExtension_Platform.wxi ?>
 </Wix>
diff --git a/src/ext/Util/wixlib/UtilBundleExtension_x86.wxs b/src/ext/Util/wixlib/UtilBootstrapperExtension_x86.wxs
index 3b458687..101cf089 100644
--- a/src/ext/Util/wixlib/UtilBundleExtension_x86.wxs
+++ b/src/ext/Util/wixlib/UtilBootstrapperExtension_x86.wxs
@@ -3,5 +3,5 @@
 
 <Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
     <?define platform=x86 ?>
-    <?include UtilBundleExtension_Platform.wxi ?>
+    <?include UtilBootstrapperExtension_Platform.wxi ?>
 </Wix>
diff --git a/src/ext/beDecor.h b/src/ext/beDecor.h
index 2c6a8818..ecd90599 100644
--- a/src/ext/beDecor.h
+++ b/src/ext/beDecor.h
@@ -3,11 +3,11 @@
 
 
 #if defined(_M_ARM64)
-#define BUNDLE_EXTENSION_DECORATION(f) L"Wix4" f L"_A64"
+#define BOOTSTRAPPER_EXTENSION_DECORATION(f) L"Wix4" f L"_A64"
 #elif defined(_M_AMD64)
-#define BUNDLE_EXTENSION_DECORATION(f) L"Wix4" f L"_X64"
+#define BOOTSTRAPPER_EXTENSION_DECORATION(f) L"Wix4" f L"_X64"
 #elif defined(_M_ARM)
-#define BUNDLE_EXTENSION_DECORATION(f) L"Wix4" f L"_ARM"
+#define BOOTSTRAPPER_EXTENSION_DECORATION(f) L"Wix4" f L"_ARM"
 #else
-#define BUNDLE_EXTENSION_DECORATION(f) L"Wix4" f L"_X86"
+#define BOOTSTRAPPER_EXTENSION_DECORATION(f) L"Wix4" f L"_X86"
 #endif
diff --git a/src/internal/SetBuildNumber/Directory.Packages.props.pp b/src/internal/SetBuildNumber/Directory.Packages.props.pp
index 17a3b257..bb0f96d8 100644
--- a/src/internal/SetBuildNumber/Directory.Packages.props.pp
+++ b/src/internal/SetBuildNumber/Directory.Packages.props.pp
@@ -13,8 +13,8 @@
     <PackageVersion Include="WixToolset.DUtil" Version="{packageversion}" />
     <PackageVersion Include="WixToolset.WcaUtil" Version="{packageversion}" />
 
-    <PackageVersion Include="WixToolset.BextUtil" Version="{packageversion}" />
     <PackageVersion Include="WixToolset.BootstrapperApplicationApi" Version="{packageversion}" />
+    <PackageVersion Include="WixToolset.BootstrapperExtensionApi" Version="{packageversion}" />
     <PackageVersion Include="WixToolset.WixStandardBootstrapperApplicationFunctionApi" Version="{packageversion}" />
 
     <PackageVersion Include="WixToolset.Data" Version="{packageversion}" />
@@ -57,17 +57,6 @@
     <PackageVersion Include="Microsoft.Win32.Registry" Version="4.7.0" />
   </ItemGroup>
 
-  <!--
-    Refer to this documentation when updating the versions of these packages:
-    https://github.com/dotnet/roslyn/blob/main/docs/wiki/NuGet-packages.md
-  -->
-  <ItemGroup>
-    <PackageVersion Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.3" />
-    <PackageVersion Include="Microsoft.CodeAnalysis.CSharp" Version="3.11.0" />
-    <PackageVersion Include="Microsoft.CodeAnalysis.CSharp.SourceGenerators.Testing.XUnit" Version="1.1.1" />
-    <PackageVersion Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="3.11.0" />
-  </ItemGroup>
-
   <ItemGroup>
     <PackageVersion Include="NuGet.Credentials" Version="6.3.3" />
     <PackageVersion Include="NuGet.Protocol" Version="6.3.3" />
diff --git a/src/wix/WixInternal.Core.TestPackage/BundleExtractor.cs b/src/wix/WixInternal.Core.TestPackage/BundleExtractor.cs
index dc4005a5..74d13132 100644
--- a/src/wix/WixInternal.Core.TestPackage/BundleExtractor.cs
+++ b/src/wix/WixInternal.Core.TestPackage/BundleExtractor.cs
@@ -16,7 +16,7 @@ namespace WixInternal.Core.TestPackage
     {
         private const string BurnNamespace = "http://wixtoolset.org/schemas/v4/2008/Burn";
         private const string BADataFileName = "BootstrapperApplicationData.xml";
-        private const string BundleExtensionDataFileName = "BundleExtensionData.xml";
+        private const string BootstrapperExtensionDataFileName = "BootstrapperExtensionData.xml";
 
         /// <summary>
         /// Extracts the BA container.
@@ -71,8 +71,8 @@ namespace WixInternal.Core.TestPackage
                 result.BADataDocument = LoadBAData(baFolderPath);
                 result.BADataNamespaceManager = GetBADataNamespaceManager(result.BADataDocument, "ba");
 
-                result.BundleExtensionDataDocument = LoadBundleExtensionData(baFolderPath);
-                result.BundleExtensionDataNamespaceManager = GetBundleExtensionDataNamespaceManager(result.BundleExtensionDataDocument, "be");
+                result.BootstrapperExtensionDataDocument = LoadBootstrapperExtensionData(baFolderPath);
+                result.BootstrapperExtensionDataNamespaceManager = GetBootstrapperExtensionDataNamespaceManager(result.BootstrapperExtensionDataDocument, "be");
             }
 
             return result;
@@ -92,15 +92,15 @@ namespace WixInternal.Core.TestPackage
         }
 
         /// <summary>
-        /// Gets an <see cref="XmlNamespaceManager"/> for BundleExtensionData.xml with the given prefix assigned to the root namespace.
+        /// Gets an <see cref="XmlNamespaceManager"/> for BootstrapperExtensionData.xml with the given prefix assigned to the root namespace.
         /// </summary>
         /// <param name="document"></param>
         /// <param name="prefix"></param>
         /// <returns></returns>
-        public static XmlNamespaceManager GetBundleExtensionDataNamespaceManager(XmlDocument document, string prefix)
+        public static XmlNamespaceManager GetBootstrapperExtensionDataNamespaceManager(XmlDocument document, string prefix)
         {
             var namespaceManager = new XmlNamespaceManager(document.NameTable);
-            namespaceManager.AddNamespace(prefix, BurnConstants.BundleExtensionDataNamespace);
+            namespaceManager.AddNamespace(prefix, BurnConstants.BootstrapperExtensionDataNamespace);
             return namespaceManager;
         }
 
@@ -134,10 +134,10 @@ namespace WixInternal.Core.TestPackage
         /// </summary>
         /// <param name="baFolderPath"></param>
         /// <returns></returns>
-        public static XmlDocument LoadBundleExtensionData(string baFolderPath)
+        public static XmlDocument LoadBootstrapperExtensionData(string baFolderPath)
         {
             var document = new XmlDocument();
-            document.Load(Path.Combine(baFolderPath, BundleExtensionDataFileName));
+            document.Load(Path.Combine(baFolderPath, BootstrapperExtensionDataFileName));
             return document;
         }
 
diff --git a/src/wix/WixInternal.Core.TestPackage/ExtractBAContainerResult.cs b/src/wix/WixInternal.Core.TestPackage/ExtractBAContainerResult.cs
index ab45d68e..1d4ba47f 100644
--- a/src/wix/WixInternal.Core.TestPackage/ExtractBAContainerResult.cs
+++ b/src/wix/WixInternal.Core.TestPackage/ExtractBAContainerResult.cs
@@ -13,14 +13,14 @@ namespace WixInternal.Core.TestPackage
     public class ExtractBAContainerResult
     {
         /// <summary>
-        /// <see cref="XmlDocument"/> for BundleExtensionData.xml.
+        /// <see cref="XmlDocument"/> for BootstrapperExtensionData.xml.
         /// </summary>
-        public XmlDocument BundleExtensionDataDocument { get; set; }
+        public XmlDocument BootstrapperExtensionDataDocument { get; set; }
 
         /// <summary>
-        /// <see cref="XmlNamespaceManager"/> for BundleExtensionData.xml.
+        /// <see cref="XmlNamespaceManager"/> for BootstrapperExtensionData.xml.
         /// </summary>
-        public XmlNamespaceManager BundleExtensionDataNamespaceManager { get; set; }
+        public XmlNamespaceManager BootstrapperExtensionDataNamespaceManager { get; set; }
 
         /// <summary>
         /// <see cref="XmlDocument"/> for BootstrapperApplicationData.xml.
@@ -53,7 +53,7 @@ namespace WixInternal.Core.TestPackage
         public bool? AttachedContainersSuccess { get; set; }
 
         /// <summary>
-        /// 
+        ///
         /// </summary>
         /// <returns></returns>
         public ExtractBAContainerResult AssertSuccess()
@@ -77,12 +77,12 @@ namespace WixInternal.Core.TestPackage
         }
 
         /// <summary>
-        /// Returns the relative path of the BundleExtension entry point dll in the given folder.
+        /// Returns the relative path of the BootstrapperExtension entry point dll in the given folder.
         /// </summary>
         /// <param name="extractedBAContainerFolderPath"></param>
         /// <param name="extensionId"></param>
         /// <returns></returns>
-        public string GetBundleExtensionFilePath(string extractedBAContainerFolderPath, string extensionId)
+        public string GetBootstrapperExtensionFilePath(string extractedBAContainerFolderPath, string extensionId)
         {
             var uxPayloads = this.SelectManifestNodes($"/burn:BurnManifest/burn:UX/burn:Payload[@Id='{extensionId}']");
             var bextPayload = uxPayloads[0];
@@ -91,7 +91,7 @@ namespace WixInternal.Core.TestPackage
         }
 
         /// <summary>
-        /// 
+        ///
         /// </summary>
         /// <param name="xpath">elements must have the 'ba' prefix</param>
         /// <returns></returns>
@@ -101,7 +101,7 @@ namespace WixInternal.Core.TestPackage
         }
 
         /// <summary>
-        /// 
+        ///
         /// </summary>
         /// <param name="xpath">elements must have the 'ba' prefix</param>
         /// <param name="ignoredAttributesByElementName">Attributes for which the value should be set to '*'.</param>
@@ -112,28 +112,28 @@ namespace WixInternal.Core.TestPackage
         }
 
         /// <summary>
-        /// 
+        ///
         /// </summary>
         /// <param name="xpath">elements must have the 'be' prefix</param>
         /// <returns></returns>
-        public XmlNodeList SelectBundleExtensionDataNodes(string xpath)
+        public XmlNodeList SelectBootstrapperExtensionDataNodes(string xpath)
         {
-            return this.BundleExtensionDataDocument.SelectNodes(xpath, this.BundleExtensionDataNamespaceManager);
+            return this.BootstrapperExtensionDataDocument.SelectNodes(xpath, this.BootstrapperExtensionDataNamespaceManager);
         }
 
         /// <summary>
-        /// 
+        ///
         /// </summary>
         /// <param name="xpath">elements must have the 'be' prefix</param>
         /// <param name="ignoredAttributesByElementName">Attributes for which the value should be set to '*'.</param>
         /// <returns></returns>
-        public string[] GetBundleExtensionTestXmlLines(string xpath, Dictionary<string, List<string>> ignoredAttributesByElementName = null)
+        public string[] GetBootstrapperExtensionTestXmlLines(string xpath, Dictionary<string, List<string>> ignoredAttributesByElementName = null)
         {
-            return this.SelectBundleExtensionDataNodes(xpath).GetTestXmlLines(ignoredAttributesByElementName);
+            return this.SelectBootstrapperExtensionDataNodes(xpath).GetTestXmlLines(ignoredAttributesByElementName);
         }
 
         /// <summary>
-        /// 
+        ///
         /// </summary>
         /// <param name="xpath">elements must have the 'burn' prefix</param>
         /// <returns></returns>
@@ -143,7 +143,7 @@ namespace WixInternal.Core.TestPackage
         }
 
         /// <summary>
-        /// 
+        ///
         /// </summary>
         /// <param name="xpath">elements must have the 'burn' prefix</param>
         /// <param name="ignoredAttributesByElementName">Attributes for which the value should be set to '*'.</param>
diff --git a/src/wix/WixToolset.Core.Burn/Bind/BaseSearchFacade.cs b/src/wix/WixToolset.Core.Burn/Bind/BaseSearchFacade.cs
index 0da78797..3974aef1 100644
--- a/src/wix/WixToolset.Core.Burn/Bind/BaseSearchFacade.cs
+++ b/src/wix/WixToolset.Core.Burn/Bind/BaseSearchFacade.cs
@@ -18,9 +18,9 @@ namespace WixToolset.Core.Burn
             {
                 writer.WriteAttributeString("Condition", this.SearchSymbol.Condition);
             }
-            if (!String.IsNullOrEmpty(this.SearchSymbol.BundleExtensionRef))
+            if (!String.IsNullOrEmpty(this.SearchSymbol.BootstrapperExtensionRef))
             {
-                writer.WriteAttributeString("ExtensionId", this.SearchSymbol.BundleExtensionRef);
+                writer.WriteAttributeString("ExtensionId", this.SearchSymbol.BootstrapperExtensionRef);
             }
         }
     }
diff --git a/src/wix/WixToolset.Core.Burn/Bind/BindBundleCommand.cs b/src/wix/WixToolset.Core.Burn/Bind/BindBundleCommand.cs
index c608e505..3dbbffa7 100644
--- a/src/wix/WixToolset.Core.Burn/Bind/BindBundleCommand.cs
+++ b/src/wix/WixToolset.Core.Burn/Bind/BindBundleCommand.cs
@@ -427,10 +427,10 @@ namespace WixToolset.Core.Burn
             // Generate the bundle extension manifest...
             string bextManifestPath;
             {
-                var command = new CreateBundleExtensionManifestCommand(section, bundleSymbol, uxPayloadIndex, this.IntermediateFolder, this.InternalBurnBackendHelper);
+                var command = new CreateBootstrapperExtensionManifestCommand(section, bundleSymbol, uxPayloadIndex, this.IntermediateFolder, this.InternalBurnBackendHelper);
                 command.Execute();
 
-                var bextManifestPayload = command.BundleExtensionManifestPayloadRow;
+                var bextManifestPayload = command.BootstrapperExtensionManifestPayloadRow;
                 bextManifestPath = command.OutputPath;
                 payloadSymbols.Add(bextManifestPayload.Id.Id, bextManifestPayload);
                 ++uxPayloadIndex;
@@ -550,7 +550,7 @@ namespace WixToolset.Core.Burn
 
             wixout.ImportDataStream(BurnConstants.BurnManifestWixOutputStreamName, manifestPath);
             wixout.ImportDataStream(BurnConstants.BootstrapperApplicationDataWixOutputStreamName, baDataPath);
-            wixout.ImportDataStream(BurnConstants.BundleExtensionDataWixOutputStreamName, bextDataPath);
+            wixout.ImportDataStream(BurnConstants.BootstrapperExtensionDataWixOutputStreamName, bextDataPath);
 
             wixout.Reopen();
 
diff --git a/src/wix/WixToolset.Core.Burn/Bind/GenerateManifestDataFromIRCommand.cs b/src/wix/WixToolset.Core.Burn/Bind/GenerateManifestDataFromIRCommand.cs
index 11b998b6..c947524b 100644
--- a/src/wix/WixToolset.Core.Burn/Bind/GenerateManifestDataFromIRCommand.cs
+++ b/src/wix/WixToolset.Core.Burn/Bind/GenerateManifestDataFromIRCommand.cs
@@ -48,7 +48,7 @@ namespace WixToolset.Core.Burn.Bind
                 var extensionSearchSymbols = kvp.Value;
                 foreach (var extensionSearchSymbol in extensionSearchSymbols)
                 {
-                    this.BackendHelper.AddBundleExtensionData(extensionId, extensionSearchSymbol, symbolIdIsIdAttribute: true);
+                    this.BackendHelper.AddBootstrapperExtensionData(extensionId, extensionSearchSymbol, symbolIdIsIdAttribute: true);
                     symbols.Remove(extensionSearchSymbol);
                 }
             }
@@ -70,7 +70,7 @@ namespace WixToolset.Core.Burn.Bind
                     case SymbolDefinitionType.WixBundleBundlePackagePayload:
                     case SymbolDefinitionType.WixBundleExePackage:
                     case SymbolDefinitionType.WixBundleExePackagePayload:
-                    case SymbolDefinitionType.WixBundleExtension:
+                    case SymbolDefinitionType.WixBootstrapperExtension:
                     case SymbolDefinitionType.WixBundleHarvestedBundlePackage:
                     case SymbolDefinitionType.WixBundleHarvestedDependencyProvider:
                     case SymbolDefinitionType.WixBundleHarvestedMsiPackage:
@@ -153,7 +153,7 @@ namespace WixToolset.Core.Burn.Bind
             switch (wixBundleCustomDataSymbol.Type)
             {
                 case WixBundleCustomDataType.BootstrapperApplication:
-                case WixBundleCustomDataType.BundleExtension:
+                case WixBundleCustomDataType.BootstrapperExtension:
                     break;
                 default:
                     return false;
@@ -195,8 +195,8 @@ namespace WixToolset.Core.Burn.Bind
                         case WixBundleCustomDataType.BootstrapperApplication:
                             writer.WriteStartElement(elementName, BurnConstants.BootstrapperApplicationDataNamespace);
                             break;
-                        case WixBundleCustomDataType.BundleExtension:
-                            writer.WriteStartElement(elementName, BurnConstants.BundleExtensionDataNamespace);
+                        case WixBundleCustomDataType.BootstrapperExtension:
+                            writer.WriteStartElement(elementName, BurnConstants.BootstrapperExtensionDataNamespace);
                             break;
                         default:
                             throw new NotImplementedException();
@@ -219,8 +219,8 @@ namespace WixToolset.Core.Burn.Bind
                     case WixBundleCustomDataType.BootstrapperApplication:
                         this.BackendHelper.AddBootstrapperApplicationData(sb.ToString());
                         break;
-                    case WixBundleCustomDataType.BundleExtension:
-                        this.BackendHelper.AddBundleExtensionData(customDataSymbol.BundleExtensionRef, sb.ToString());
+                    case WixBundleCustomDataType.BootstrapperExtension:
+                        this.BackendHelper.AddBootstrapperExtensionData(customDataSymbol.BootstrapperExtensionRef, sb.ToString());
                         break;
                     default:
                         throw new NotImplementedException();
diff --git a/src/wix/WixToolset.Core.Burn/Bundles/BurnCommon.cs b/src/wix/WixToolset.Core.Burn/Bundles/BurnCommon.cs
index 95673ab0..863a14aa 100644
--- a/src/wix/WixToolset.Core.Burn/Bundles/BurnCommon.cs
+++ b/src/wix/WixToolset.Core.Burn/Bundles/BurnCommon.cs
@@ -12,7 +12,7 @@ namespace WixToolset.Core.Burn.Bundles
     /// <summary>
     /// Common functionality for Burn PE Writer &amp; Reader for the WiX toolset.
     /// </summary>
-    /// <remarks>This class encapsulates common functionality related to 
+    /// <remarks>This class encapsulates common functionality related to
     /// bundled/chained setup packages.</remarks>
     /// <example>
     /// </example>
@@ -25,7 +25,7 @@ namespace WixToolset.Core.Burn.Bundles
 
         public const string BADataFileName = "BootstrapperApplicationData.xml";
 
-        public const string BundleExtensionDataFileName = "BundleExtensionData.xml";
+        public const string BootstrapperExtensionDataFileName = "BootstrapperExtensionData.xml";
 
         // See WinNT.h for details about the PE format, including the
         // structure and offsets for IMAGE_DOS_HEADER, IMAGE_NT_HEADERS32,
@@ -320,7 +320,7 @@ namespace WixToolset.Core.Burn.Bundles
 
                 this.wixburnRawDataSize = BurnCommon.ReadUInt32(bytes, IMAGE_SECTION_HEADER_OFFSET_SIZEOFRAWDATA);
 
-                // we need 52 bytes for the manifest header, which is always going to fit in 
+                // we need 52 bytes for the manifest header, which is always going to fit in
                 // the smallest alignment (512 bytes), but just to be paranoid...
                 if (BURN_SECTION_MIN_SIZE > this.wixburnRawDataSize)
                 {
diff --git a/src/wix/WixToolset.Core.Burn/Bundles/CreateBundleExtensionManifestCommand.cs b/src/wix/WixToolset.Core.Burn/Bundles/CreateBootstrapperExtensionManifestCommand.cs
index ab6dcea1..045fe5d6 100644
--- a/src/wix/WixToolset.Core.Burn/Bundles/CreateBundleExtensionManifestCommand.cs
+++ b/src/wix/WixToolset.Core.Burn/Bundles/CreateBootstrapperExtensionManifestCommand.cs
@@ -11,9 +11,9 @@ namespace WixToolset.Core.Burn.Bundles
     using WixToolset.Data.Burn;
     using WixToolset.Data.Symbols;
 
-    internal class CreateBundleExtensionManifestCommand
+    internal class CreateBootstrapperExtensionManifestCommand
     {
-        public CreateBundleExtensionManifestCommand(IntermediateSection section, WixBundleSymbol bundleSymbol, int lastUXPayloadIndex, string intermediateFolder, IInternalBurnBackendHelper internalBurnBackendHelper)
+        public CreateBootstrapperExtensionManifestCommand(IntermediateSection section, WixBundleSymbol bundleSymbol, int lastUXPayloadIndex, string intermediateFolder, IInternalBurnBackendHelper internalBurnBackendHelper)
         {
             this.Section = section;
             this.BundleSymbol = bundleSymbol;
@@ -32,18 +32,18 @@ namespace WixToolset.Core.Burn.Bundles
 
         private string IntermediateFolder { get; }
 
-        public WixBundlePayloadSymbol BundleExtensionManifestPayloadRow { get; private set; }
+        public WixBundlePayloadSymbol BootstrapperExtensionManifestPayloadRow { get; private set; }
 
         public string OutputPath { get; private set; }
 
         public void Execute()
         {
-            this.OutputPath = this.CreateBundleExtensionManifest();
+            this.OutputPath = this.CreateBootstrapperExtensionManifest();
 
-            this.BundleExtensionManifestPayloadRow = this.CreateBundleExtensionManifestPayloadRow(this.OutputPath);
+            this.BootstrapperExtensionManifestPayloadRow = this.CreateBootstrapperExtensionManifestPayloadRow(this.OutputPath);
         }
 
-        private string CreateBundleExtensionManifest()
+        private string CreateBootstrapperExtensionManifest()
         {
             var path = Path.Combine(this.IntermediateFolder, "wix-bextdata.xml");
 
@@ -53,9 +53,9 @@ namespace WixToolset.Core.Burn.Bundles
             {
                 writer.Formatting = Formatting.Indented;
                 writer.WriteStartDocument();
-                writer.WriteStartElement("BundleExtensionData", BurnConstants.BundleExtensionDataNamespace);
+                writer.WriteStartElement("BootstrapperExtensionData", BurnConstants.BootstrapperExtensionDataNamespace);
 
-                this.InternalBurnBackendHelper.WriteBundleExtensionData(writer);
+                this.InternalBurnBackendHelper.WriteBootstrapperExtensionData(writer);
 
                 writer.WriteEndElement();
                 writer.WriteEndDocument();
@@ -64,9 +64,9 @@ namespace WixToolset.Core.Burn.Bundles
             return path;
         }
 
-        private WixBundlePayloadSymbol CreateBundleExtensionManifestPayloadRow(string bextManifestPath)
+        private WixBundlePayloadSymbol CreateBootstrapperExtensionManifestPayloadRow(string bextManifestPath)
         {
-            var generatedId = this.InternalBurnBackendHelper.GenerateIdentifier("ux", BurnCommon.BundleExtensionDataFileName);
+            var generatedId = this.InternalBurnBackendHelper.GenerateIdentifier("ux", BurnCommon.BootstrapperExtensionDataFileName);
 
             this.Section.AddSymbol(new WixGroupSymbol(this.BundleSymbol.SourceLineNumbers)
             {
@@ -78,7 +78,7 @@ namespace WixToolset.Core.Burn.Bundles
 
             var symbol = this.Section.AddSymbol(new WixBundlePayloadSymbol(this.BundleSymbol.SourceLineNumbers, new Identifier(AccessModifier.Section, generatedId))
             {
-                Name = BurnCommon.BundleExtensionDataFileName,
+                Name = BurnCommon.BootstrapperExtensionDataFileName,
                 SourceFile = new IntermediateFieldPathValue { Path = bextManifestPath },
                 Compressed = true,
                 UnresolvedSourceFile = bextManifestPath,
diff --git a/src/wix/WixToolset.Core.Burn/Bundles/CreateBurnManifestCommand.cs b/src/wix/WixToolset.Core.Burn/Bundles/CreateBurnManifestCommand.cs
index bb057293..193bfcc8 100644
--- a/src/wix/WixToolset.Core.Burn/Bundles/CreateBurnManifestCommand.cs
+++ b/src/wix/WixToolset.Core.Burn/Bundles/CreateBurnManifestCommand.cs
@@ -702,16 +702,16 @@ namespace WixToolset.Core.Burn.Bundles
                     writer.WriteEndElement();
                 }
 
-                // Write the BundleExtension elements.
-                var bundleExtensions = this.Section.Symbols.OfType<WixBundleExtensionSymbol>();
+                // Write the BootstrapperExtension elements.
+                var bootstrapperExtensions = this.Section.Symbols.OfType<WixBootstrapperExtensionSymbol>();
                 var uxPayloadsById = this.UXContainerPayloads.ToDictionary(p => p.Id.Id);
 
-                foreach (var bundleExtension in bundleExtensions)
+                foreach (var bootstrapperExtension in bootstrapperExtensions)
                 {
-                    var entryPayload = uxPayloadsById[bundleExtension.PayloadRef];
+                    var entryPayload = uxPayloadsById[bootstrapperExtension.PayloadRef];
 
-                    writer.WriteStartElement("BundleExtension");
-                    writer.WriteAttributeString("Id", bundleExtension.Id.Id);
+                    writer.WriteStartElement("BootstrapperExtension");
+                    writer.WriteAttributeString("Id", bootstrapperExtension.Id.Id);
                     writer.WriteAttributeString("EntryPayloadSourcePath", entryPayload.EmbeddedId);
 
                     writer.WriteEndElement();
diff --git a/src/wix/WixToolset.Core.Burn/Bundles/OrderSearchesCommand.cs b/src/wix/WixToolset.Core.Burn/Bundles/OrderSearchesCommand.cs
index 01d5657b..60f375e5 100644
--- a/src/wix/WixToolset.Core.Burn/Bundles/OrderSearchesCommand.cs
+++ b/src/wix/WixToolset.Core.Burn/Bundles/OrderSearchesCommand.cs
@@ -329,7 +329,7 @@ namespace WixToolset.Core.Burn.Bundles
                 .OfType<WixSetVariableSymbol>()
                 .ToDictionary(t => t.Id.Id);
             var extensionSearchesById = this.Section.Symbols
-                .Where(t => t.Definition.HasTag(BurnConstants.BundleExtensionSearchSymbolDefinitionTag))
+                .Where(t => t.Definition.HasTag(BurnConstants.BootstrapperExtensionSearchSymbolDefinitionTag))
                 .ToDictionary(t => t.Id.Id);
 
             foreach (var searchId in sortedIds)
@@ -348,10 +348,10 @@ namespace WixToolset.Core.Burn.Bundles
                 {
                     orderedSearchFacades.Add(new ExtensionSearchFacade(searchSymbol));
 
-                    if (!extensionSearchSymbolsByExtensionId.TryGetValue(searchSymbol.BundleExtensionRef, out var extensionSearchSymbols))
+                    if (!extensionSearchSymbolsByExtensionId.TryGetValue(searchSymbol.BootstrapperExtensionRef, out var extensionSearchSymbols))
                     {
                         extensionSearchSymbols = new List<IntermediateSymbol>();
-                        extensionSearchSymbolsByExtensionId[searchSymbol.BundleExtensionRef] = extensionSearchSymbols;
+                        extensionSearchSymbolsByExtensionId[searchSymbol.BootstrapperExtensionRef] = extensionSearchSymbols;
                     }
                     extensionSearchSymbols.Add(extensionSearchSymbol);
                 }
diff --git a/src/wix/WixToolset.Core.Burn/ExtensibilityServices/BurnBackendHelper.cs b/src/wix/WixToolset.Core.Burn/ExtensibilityServices/BurnBackendHelper.cs
index f2b3587d..93de0d2c 100644
--- a/src/wix/WixToolset.Core.Burn/ExtensibilityServices/BurnBackendHelper.cs
+++ b/src/wix/WixToolset.Core.Burn/ExtensibilityServices/BurnBackendHelper.cs
@@ -25,7 +25,7 @@ namespace WixToolset.Core.Burn.ExtensibilityServices
 
         private ManifestData BootstrapperApplicationManifestData { get; } = new ManifestData();
 
-        private Dictionary<string, ManifestData> BundleExtensionDataById { get; } = new Dictionary<string, ManifestData>();
+        private Dictionary<string, ManifestData> BootstrapperExtensionDataById { get; } = new Dictionary<string, ManifestData>();
 
         public BurnBackendHelper(IServiceProvider serviceProvider)
         {
@@ -149,16 +149,16 @@ namespace WixToolset.Core.Burn.ExtensibilityServices
             this.BootstrapperApplicationManifestData.AddSymbol(symbol, symbolIdIsIdAttribute, BurnConstants.BootstrapperApplicationDataNamespace);
         }
 
-        public void AddBundleExtensionData(string extensionId, string xml)
+        public void AddBootstrapperExtensionData(string extensionId, string xml)
         {
-            var manifestData = this.GetBundleExtensionManifestData(extensionId);
+            var manifestData = this.GetBootstrapperExtensionManifestData(extensionId);
             manifestData.AddXml(xml);
         }
 
-        public void AddBundleExtensionData(string extensionId, IntermediateSymbol symbol, bool symbolIdIsIdAttribute = false)
+        public void AddBootstrapperExtensionData(string extensionId, IntermediateSymbol symbol, bool symbolIdIsIdAttribute = false)
         {
-            var manifestData = this.GetBundleExtensionManifestData(extensionId);
-            manifestData.AddSymbol(symbol, symbolIdIsIdAttribute, BurnConstants.BundleExtensionDataNamespace);
+            var manifestData = this.GetBootstrapperExtensionManifestData(extensionId);
+            manifestData.AddSymbol(symbol, symbolIdIsIdAttribute, BurnConstants.BootstrapperExtensionDataNamespace);
         }
 
         #endregion
@@ -204,9 +204,9 @@ namespace WixToolset.Core.Burn.ExtensibilityServices
             this.BootstrapperApplicationManifestData.Write(writer);
         }
 
-        public void WriteBundleExtensionData(XmlWriter writer)
+        public void WriteBootstrapperExtensionData(XmlWriter writer)
         {
-            foreach (var kvp in this.BundleExtensionDataById)
+            foreach (var kvp in this.BootstrapperExtensionDataById)
             {
                 this.WriteExtension(writer, kvp.Key, kvp.Value);
             }
@@ -214,17 +214,17 @@ namespace WixToolset.Core.Burn.ExtensibilityServices
 
         #endregion
 
-        private ManifestData GetBundleExtensionManifestData(string extensionId)
+        private ManifestData GetBootstrapperExtensionManifestData(string extensionId)
         {
             if (!this.backendHelper.IsValidIdentifier(extensionId))
             {
                 throw new ArgumentException($"'{extensionId}' is not a valid extensionId");
             }
 
-            if (!this.BundleExtensionDataById.TryGetValue(extensionId, out var manifestData))
+            if (!this.BootstrapperExtensionDataById.TryGetValue(extensionId, out var manifestData))
             {
                 manifestData = new ManifestData();
-                this.BundleExtensionDataById.Add(extensionId, manifestData);
+                this.BootstrapperExtensionDataById.Add(extensionId, manifestData);
             }
 
             return manifestData;
@@ -232,7 +232,7 @@ namespace WixToolset.Core.Burn.ExtensibilityServices
 
         private void WriteExtension(XmlWriter writer, string extensionId, ManifestData manifestData)
         {
-            writer.WriteStartElement("BundleExtension");
+            writer.WriteStartElement("BootstrapperExtension");
 
             writer.WriteAttributeString("Id", extensionId);
 
diff --git a/src/wix/WixToolset.Core.Burn/IInternalBurnBackendHelper.cs b/src/wix/WixToolset.Core.Burn/IInternalBurnBackendHelper.cs
index 59c4f20f..44517564 100644
--- a/src/wix/WixToolset.Core.Burn/IInternalBurnBackendHelper.cs
+++ b/src/wix/WixToolset.Core.Burn/IInternalBurnBackendHelper.cs
@@ -9,6 +9,6 @@ namespace WixToolset.Core.Burn
     {
         void WriteBootstrapperApplicationData(XmlWriter writer);
 
-        void WriteBundleExtensionData(XmlWriter writer);
+        void WriteBootstrapperExtensionData(XmlWriter writer);
     }
 }
diff --git a/src/wix/WixToolset.Core/Compiler.cs b/src/wix/WixToolset.Core/Compiler.cs
index 65c4be50..d13f1a68 100644
--- a/src/wix/WixToolset.Core/Compiler.cs
+++ b/src/wix/WixToolset.Core/Compiler.cs
@@ -6083,11 +6083,11 @@ namespace WixToolset.Core
                     case "BundleCustomDataRef":
                         this.ParseBundleCustomDataRefElement(child);
                         break;
-                    case "BundleExtension":
-                        this.ParseBundleExtensionElement(child);
+                    case "BootstrapperExtension":
+                        this.ParseBootstrapperExtensionElement(child);
                         break;
-                    case "BundleExtensionRef":
-                        this.ParseSimpleRefElement(child, SymbolDefinitions.WixBundleExtension);
+                    case "BootstrapperExtensionRef":
+                        this.ParseSimpleRefElement(child, SymbolDefinitions.WixBootstrapperExtension);
                         break;
                     case "ComplianceCheck":
                         this.ParseComplianceCheckElement(child);
diff --git a/src/wix/WixToolset.Core/Compiler_Bundle.cs b/src/wix/WixToolset.Core/Compiler_Bundle.cs
index baf59cfc..fcf31014 100644
--- a/src/wix/WixToolset.Core/Compiler_Bundle.cs
+++ b/src/wix/WixToolset.Core/Compiler_Bundle.cs
@@ -312,11 +312,13 @@ namespace WixToolset.Core
                         case "BundleCustomDataRef":
                             this.ParseBundleCustomDataRefElement(child);
                             break;
-                        case "BundleExtension":
-                            this.ParseBundleExtensionElement(child);
+                        case "BundleExtension":     // kept for backward compatibility
+                        case "BootstrapperExtension":
+                            this.ParseBootstrapperExtensionElement(child);
                             break;
-                        case "BundleExtensionRef":
-                            this.ParseSimpleRefElement(child, SymbolDefinitions.WixBundleExtension);
+                        case "BundleExtensionRef":  // kept for backward compatibility
+                        case "BootstrapperExtensionRef":
+                            this.ParseSimpleRefElement(child, SymbolDefinitions.WixBootstrapperExtension);
                             break;
                         case "OptionalUpdateRegistration":
                             this.ParseOptionalUpdateRegistrationElement(child, manufacturer, parentName, name);
@@ -916,18 +918,19 @@ namespace WixToolset.Core
                                 case "bootstrapperApplication":
                                     customDataType = WixBundleCustomDataType.BootstrapperApplication;
                                     break;
-                                case "bundleExtension":
-                                    customDataType = WixBundleCustomDataType.BundleExtension;
+                                case "bundleExtension":         // kept for backward compatibility
+                                case "bootstrapperExtension":
+                                    customDataType = WixBundleCustomDataType.BootstrapperExtension;
                                     break;
                                 default:
-                                    this.Core.Write(ErrorMessages.IllegalAttributeValue(sourceLineNumbers, node.Name.LocalName, "Type", typeValue, "bootstrapperApplication", "bundleExtension"));
+                                    this.Core.Write(ErrorMessages.IllegalAttributeValue(sourceLineNumbers, node.Name.LocalName, "Type", typeValue, "bootstrapperApplication", "bootstrapperExtension"));
                                     customDataType = WixBundleCustomDataType.Unknown; // set a value to prevent expected attribute error below.
                                     break;
                             }
                             break;
                         case "ExtensionId":
                             extensionId = this.Core.GetAttributeIdentifierValue(sourceLineNumbers, attrib);
-                            this.Core.CreateSimpleReference(sourceLineNumbers, SymbolDefinitions.WixBundleExtension, extensionId);
+                            this.Core.CreateSimpleReference(sourceLineNumbers, SymbolDefinitions.WixBootstrapperExtension, extensionId);
                             break;
                         default:
                             this.Core.UnexpectedAttribute(node, attrib);
@@ -948,7 +951,7 @@ namespace WixToolset.Core
             var hasExtensionId = null != extensionId;
             if (!customDataType.HasValue)
             {
-                customDataType = hasExtensionId ? WixBundleCustomDataType.BundleExtension : WixBundleCustomDataType.BootstrapperApplication;
+                customDataType = hasExtensionId ? WixBundleCustomDataType.BootstrapperExtension : WixBundleCustomDataType.BootstrapperApplication;
             }
 
             if (!customDataType.HasValue)
@@ -962,9 +965,9 @@ namespace WixToolset.Core
                     this.Core.Write(ErrorMessages.IllegalAttributeWithOtherAttribute(sourceLineNumbers, node.Name.LocalName, "ExtensonId", "Type", "bootstrapperApplication"));
                 }
             }
-            else if (customDataType.Value == WixBundleCustomDataType.BundleExtension)
+            else if (customDataType.Value == WixBundleCustomDataType.BootstrapperExtension)
             {
-                this.Core.Write(ErrorMessages.ExpectedAttribute(sourceLineNumbers, node.Name.LocalName, "ExtensionId", "Type", "bundleExtension"));
+                this.Core.Write(ErrorMessages.ExpectedAttribute(sourceLineNumbers, node.Name.LocalName, "ExtensionId", "Type", "bootstrapperExtension"));
             }
 
             foreach (var child in node.Elements())
@@ -1007,7 +1010,7 @@ namespace WixToolset.Core
                     {
                         AttributeNames = attributeNames,
                         Type = customDataType.Value,
-                        BundleExtensionRef = extensionId,
+                        BootstrapperExtensionRef = extensionId,
                     });
                 }
             }
@@ -1185,10 +1188,10 @@ namespace WixToolset.Core
         }
 
         /// <summary>
-        /// Parse the BundleExtension element.
+        /// Parse the BootstrapperExtension element.
         /// </summary>
         /// <param name="node">Element to parse</param>
-        private void ParseBundleExtensionElement(XElement node)
+        private void ParseBootstrapperExtensionElement(XElement node)
         {
             var sourceLineNumbers = Preprocessor.GetSourceLineNumbers(node);
             var compilerPayload = new CompilerPayload(this.Core, sourceLineNumbers, node);
@@ -1261,10 +1264,10 @@ namespace WixToolset.Core
                 }
             }
 
-            // Add the BundleExtension.
+            // Add the BootstrapperExtension.
             if (!this.Core.EncounteredError)
             {
-                this.Core.AddSymbol(new WixBundleExtensionSymbol(sourceLineNumbers, compilerPayload.Id)
+                this.Core.AddSymbol(new WixBootstrapperExtensionSymbol(sourceLineNumbers, compilerPayload.Id)
                 {
                     PayloadRef = compilerPayload.Id.Id,
                 });
diff --git a/src/wix/WixToolset.Core/ExtensibilityServices/ParseHelper.cs b/src/wix/WixToolset.Core/ExtensibilityServices/ParseHelper.cs
index 5ccaffdc..52a7cf12 100644
--- a/src/wix/WixToolset.Core/ExtensibilityServices/ParseHelper.cs
+++ b/src/wix/WixToolset.Core/ExtensibilityServices/ParseHelper.cs
@@ -242,7 +242,7 @@ namespace WixToolset.Core.ExtensibilityServices
             });
         }
 
-        public void CreateWixSearchSymbol(IntermediateSection section, SourceLineNumber sourceLineNumbers, string elementName, Identifier id, string variable, string condition, string after, string bundleExtensionId)
+        public void CreateWixSearchSymbol(IntermediateSection section, SourceLineNumber sourceLineNumbers, string elementName, Identifier id, string variable, string condition, string after, string bootstrapperExtensionId)
         {
             if (variable == null)
             {
@@ -257,7 +257,7 @@ namespace WixToolset.Core.ExtensibilityServices
             {
                 Variable = variable,
                 Condition = condition,
-                BundleExtensionRef = bundleExtensionId,
+                BootstrapperExtensionRef = bootstrapperExtensionId,
             });
 
             if (after != null)
@@ -267,9 +267,9 @@ namespace WixToolset.Core.ExtensibilityServices
                 this.CreateWixSearchRelationSymbol(section, sourceLineNumbers, id, after, 2);
             }
 
-            if (!String.IsNullOrEmpty(bundleExtensionId))
+            if (!String.IsNullOrEmpty(bootstrapperExtensionId))
             {
-                this.CreateSimpleReference(section, sourceLineNumbers, SymbolDefinitions.WixBundleExtension, bundleExtensionId);
+                this.CreateSimpleReference(section, sourceLineNumbers, SymbolDefinitions.WixBootstrapperExtension, bootstrapperExtensionId);
             }
         }
 
diff --git a/src/wix/test/Example.Extension/Data/example.wxs b/src/wix/test/Example.Extension/Data/example.wxs
index dc0a68ec..762b98e3 100644
--- a/src/wix/test/Example.Extension/Data/example.wxs
+++ b/src/wix/test/Example.Extension/Data/example.wxs
@@ -17,6 +17,6 @@
   </Fragment>
 
   <Fragment>
-    <BundleExtension Id="ExampleBundleExtension" SourceFile="example.txt" />
+    <BootstrapperExtension Id="ExampleBootstrapperExtension" SourceFile="example.txt" />
   </Fragment>
 </Wix>
diff --git a/src/wix/test/Example.Extension/ExampleCompilerExtension.cs b/src/wix/test/Example.Extension/ExampleCompilerExtension.cs
index bdce8754..f34cf963 100644
--- a/src/wix/test/Example.Extension/ExampleCompilerExtension.cs
+++ b/src/wix/test/Example.Extension/ExampleCompilerExtension.cs
@@ -11,7 +11,7 @@ namespace Example.Extension
 
     internal class ExampleCompilerExtension : BaseCompilerExtension
     {
-        private const string BundleExtensionId = "ExampleBundleExtension";
+        private const string BootstrapperExtensionId = "ExampleBootstrapperExtension";
 
         public override XNamespace Namespace => ExampleConstants.Namespace;
 
@@ -228,7 +228,7 @@ namespace Example.Extension
 
             if (!this.Messaging.EncounteredError)
             {
-                this.ParseHelper.CreateWixSearchSymbol(section, sourceLineNumbers, element.Name.LocalName, id, variable, condition, after, BundleExtensionId);
+                this.ParseHelper.CreateWixSearchSymbol(section, sourceLineNumbers, element.Name.LocalName, id, variable, condition, after, BootstrapperExtensionId);
             }
 
             if (!this.Messaging.EncounteredError)
diff --git a/src/wix/test/Example.Extension/ExampleSymbolDefinitions.cs b/src/wix/test/Example.Extension/ExampleSymbolDefinitions.cs
index 83b675c9..19704bc4 100644
--- a/src/wix/test/Example.Extension/ExampleSymbolDefinitions.cs
+++ b/src/wix/test/Example.Extension/ExampleSymbolDefinitions.cs
@@ -33,7 +33,7 @@ namespace Example.Extension
 
         static ExampleSymbolDefinitions()
         {
-            ExampleSearch.AddTag(BurnConstants.BundleExtensionSearchSymbolDefinitionTag);
+            ExampleSearch.AddTag(BurnConstants.BootstrapperExtensionSearchSymbolDefinitionTag);
         }
 
         public static bool TryGetSymbolType(string name, out ExampleSymbolDefinitionType type)
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/BundleFixture.cs b/src/wix/test/WixToolsetTest.CoreIntegration/BundleFixture.cs
index 935d20b5..3280c608 100644
--- a/src/wix/test/WixToolsetTest.CoreIntegration/BundleFixture.cs
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/BundleFixture.cs
@@ -131,8 +131,8 @@ namespace WixToolsetTest.CoreIntegration
                     var extractedBaManifestData = File.ReadAllText(Path.Combine(baFolderPath, "BootstrapperApplicationData.xml"), Encoding.UTF8);
                     WixAssert.StringEqual(extractedBaManifestData, baManifestData);
 
-                    var bextManifestData = wixOutput.GetData(BurnConstants.BundleExtensionDataWixOutputStreamName);
-                    var extractedBextManifestData = File.ReadAllText(Path.Combine(baFolderPath, "BundleExtensionData.xml"), Encoding.UTF8);
+                    var bextManifestData = wixOutput.GetData(BurnConstants.BootstrapperExtensionDataWixOutputStreamName);
+                    var extractedBextManifestData = File.ReadAllText(Path.Combine(baFolderPath, "BootstrapperExtensionData.xml"), Encoding.UTF8);
                     WixAssert.StringEqual(extractedBextManifestData, bextManifestData);
 
                     foreach (XmlAttribute attribute in extractResult.ManifestDocument.DocumentElement.Attributes)
@@ -631,8 +631,8 @@ namespace WixToolsetTest.CoreIntegration
                 WixAssert.CompareLineByLine(new string[]
                 {
                     "Error 8002: The Payload 'DuplicatePayloadNames.wxs' has a duplicate Name 'fakeba.dll' in the BA container. When extracting the container at runtime, the file will get overwritten.",
+                    "Error 8002: The Payload 'uxmKgAFS4cS31ZH_Myfqo5J4kHixQ' has a duplicate Name 'BootstrapperExtensionData.xml' in the BA container. When extracting the container at runtime, the file will get overwritten.",
                     "Error 8002: The Payload 'uxTxMXPVMXwQrPTMIGa5WGt93w0Ns' has a duplicate Name 'BootstrapperApplicationData.xml' in the BA container. When extracting the container at runtime, the file will get overwritten.",
-                    "Error 8002: The Payload 'uxYRbgitOs0K878jn5L_z7LdJ21KI' has a duplicate Name 'BundleExtensionData.xml' in the BA container. When extracting the container at runtime, the file will get overwritten.",
                     "Error 8003: The location of the payload related to the previous error.",
                     "Error 8003: The location of the payload related to the previous error.",
                     "Error 8003: The location of the payload related to the previous error.",
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/BundleManifestFixture.cs b/src/wix/test/WixToolsetTest.CoreIntegration/BundleManifestFixture.cs
index 3c97ceb1..f06d1e53 100644
--- a/src/wix/test/WixToolsetTest.CoreIntegration/BundleManifestFixture.cs
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/BundleManifestFixture.cs
@@ -192,7 +192,7 @@ namespace WixToolsetTest.CoreIntegration
         }
 
         [Fact]
-        public void PopulatesBEManifestWithBundleExtensionBundleCustomData()
+        public void PopulatesBEManifestWithBootstrapperExtensionBundleCustomData()
         {
             var folder = TestData.Get(@"TestData");
 
@@ -222,7 +222,7 @@ namespace WixToolsetTest.CoreIntegration
                 var extractResult = BundleExtractor.ExtractBAContainer(null, bundlePath, baFolderPath, extractFolderPath);
                 extractResult.AssertSuccess();
 
-                var customElements = extractResult.GetBundleExtensionTestXmlLines("/be:BundleExtensionData/be:BundleExtension[@Id='CustomTableExtension']/be:BundleCustomTableBE");
+                var customElements = extractResult.GetBootstrapperExtensionTestXmlLines("/be:BootstrapperExtensionData/be:BootstrapperExtension[@Id='CustomTableExtension']/be:BundleCustomTableBE");
                 WixAssert.CompareLineByLine(new[]
                 {
                     "<BundleCustomTableBE Id='one' Column2='two' />",
@@ -233,7 +233,7 @@ namespace WixToolsetTest.CoreIntegration
         }
 
         [Fact]
-        public void PopulatesManifestWithBundleExtension()
+        public void PopulatesManifestWithBootstrapperExtension()
         {
             var folder = TestData.Get(@"TestData");
 
@@ -248,8 +248,8 @@ namespace WixToolsetTest.CoreIntegration
                 var result = WixRunner.Execute(new[]
                 {
                     "build",
-                    Path.Combine(folder, "BundleExtension", "BundleExtension.wxs"),
-                    Path.Combine(folder, "BundleExtension", "SimpleBundleExtension.wxs"),
+                    Path.Combine(folder, "BootstrapperExtension", "BootstrapperExtension.wxs"),
+                    Path.Combine(folder, "BootstrapperExtension", "SimpleBootstrapperExtension.wxs"),
                     Path.Combine(folder, "BundleWithPackageGroupRef", "MinimalPackageGroup.wxs"),
                     Path.Combine(folder, "BundleWithPackageGroupRef", "Bundle.wxs"),
                     "-bindpath", Path.Combine(folder, "SimpleBundle", "data"),
@@ -264,22 +264,22 @@ namespace WixToolsetTest.CoreIntegration
                 var extractResult = BundleExtractor.ExtractBAContainer(null, bundlePath, baFolderPath, extractFolderPath);
                 extractResult.AssertSuccess();
 
-                var bundleExtensions = extractResult.GetManifestTestXmlLines("/burn:BurnManifest/burn:BundleExtension");
+                var bootstrapperExtensions = extractResult.GetManifestTestXmlLines("/burn:BurnManifest/burn:BootstrapperExtension");
                 WixAssert.CompareLineByLine(new[]
                 {
-                    "<BundleExtension Id='ExampleBext' EntryPayloadSourcePath='u1' />",
-                }, bundleExtensions);
+                    "<BootstrapperExtension Id='ExampleBext' EntryPayloadSourcePath='u1' />",
+                }, bootstrapperExtensions);
 
-                var bundleExtensionPayloads = extractResult.GetManifestTestXmlLines("/burn:BurnManifest/burn:UX/burn:Payload[@Id='ExampleBext']");
+                var bootstrapperExtensionPayloads = extractResult.GetManifestTestXmlLines("/burn:BurnManifest/burn:UX/burn:Payload[@Id='ExampleBext']");
                 WixAssert.CompareLineByLine(new[]
                 {
                     "<Payload Id='ExampleBext' FilePath='fakebext.dll' SourcePath='u1' />",
-                }, bundleExtensionPayloads);
+                }, bootstrapperExtensionPayloads);
             }
         }
 
         [Fact]
-        public void PopulatesManifestWithBundleExtensionSearches()
+        public void PopulatesManifestWithBootstrapperExtensionSearches()
         {
             var folder = TestData.Get(@"TestData");
 
@@ -294,8 +294,8 @@ namespace WixToolsetTest.CoreIntegration
                 var result = WixRunner.Execute(new[]
                 {
                     "build",
-                    Path.Combine(folder, "BundleExtension", "BundleExtensionSearches.wxs"),
-                    Path.Combine(folder, "BundleExtension", "BundleWithSearches.wxs"),
+                    Path.Combine(folder, "BootstrapperExtension", "BootstrapperExtensionSearches.wxs"),
+                    Path.Combine(folder, "BootstrapperExtension", "BundleWithSearches.wxs"),
                     Path.Combine(folder, "BundleWithPackageGroupRef", "MinimalPackageGroup.wxs"),
                     Path.Combine(folder, "BundleWithPackageGroupRef", "Bundle.wxs"),
                     "-ext", ExtensionPaths.ExampleExtensionPath,
@@ -311,29 +311,29 @@ namespace WixToolsetTest.CoreIntegration
                 var extractResult = BundleExtractor.ExtractBAContainer(null, bundlePath, baFolderPath, extractFolderPath);
                 extractResult.AssertSuccess();
 
-                var bundleExtensions = extractResult.GetManifestTestXmlLines("/burn:BurnManifest/burn:BundleExtension");
+                var bootstrapperExtensions = extractResult.GetManifestTestXmlLines("/burn:BurnManifest/burn:BootstrapperExtension");
                 WixAssert.CompareLineByLine(new[]
                 {
-                    "<BundleExtension Id='ExampleBundleExtension' EntryPayloadSourcePath='u1' />",
-                }, bundleExtensions);
+                    "<BootstrapperExtension Id='ExampleBootstrapperExtension' EntryPayloadSourcePath='u1' />",
+                }, bootstrapperExtensions);
 
                 var extensionSearches = extractResult.GetManifestTestXmlLines("/burn:BurnManifest/burn:ExtensionSearch");
                 WixAssert.CompareLineByLine(new[]
                 {
-                    "<ExtensionSearch Id='ExampleSearchBar' Variable='SearchBar' Condition='WixBundleInstalled' ExtensionId='ExampleBundleExtension' />",
-                    "<ExtensionSearch Id='ExampleSearchFoo' Variable='SearchFoo' ExtensionId='ExampleBundleExtension' />",
+                    "<ExtensionSearch Id='ExampleSearchBar' Variable='SearchBar' Condition='WixBundleInstalled' ExtensionId='ExampleBootstrapperExtension' />",
+                    "<ExtensionSearch Id='ExampleSearchFoo' Variable='SearchFoo' ExtensionId='ExampleBootstrapperExtension' />",
                 }, extensionSearches);
 
-                var bundleExtensionDatas = extractResult.GetBundleExtensionTestXmlLines("/be:BundleExtensionData/be:BundleExtension[@Id='ExampleBundleExtension']");
+                var bootstrapperExtensionDatas = extractResult.GetBootstrapperExtensionTestXmlLines("/be:BootstrapperExtensionData/be:BootstrapperExtension[@Id='ExampleBootstrapperExtension']");
                 WixAssert.CompareLineByLine(new[]
                 {
-                    "<BundleExtension Id='ExampleBundleExtension'>" +
+                    "<BootstrapperExtension Id='ExampleBootstrapperExtension'>" +
                     "<ExampleSearch Id='ExampleSearchBar' SearchFor='Bar' />" +
                     "<ExampleSearch Id='ExampleSearchFoo' SearchFor='Foo' />" +
-                    "</BundleExtension>"
-                }, bundleExtensionDatas);
+                    "</BootstrapperExtension>"
+                }, bootstrapperExtensionDatas);
 
-                var exampleSearches = extractResult.GetBundleExtensionTestXmlLines("/be:BundleExtensionData/be:BundleExtension[@Id='ExampleBundleExtension']/be:ExampleSearch");
+                var exampleSearches = extractResult.GetBootstrapperExtensionTestXmlLines("/be:BootstrapperExtensionData/be:BootstrapperExtension[@Id='ExampleBootstrapperExtension']/be:ExampleSearch");
                 WixAssert.CompareLineByLine(new[]
                 {
                     "<ExampleSearch Id='ExampleSearchBar' SearchFor='Bar' />",
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BadInput/DuplicatePayloadNames.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BadInput/DuplicatePayloadNames.wxs
index 57a85669..eead3c36 100644
--- a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BadInput/DuplicatePayloadNames.wxs
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BadInput/DuplicatePayloadNames.wxs
@@ -5,7 +5,7 @@
         <PayloadGroup Id="override ExtraBoostrapperApplicationPayloads">
             <Payload Id="DuplicatePayloadNames.wxs" SourceFile="$(sys.SOURCEFILEPATH)" Name="fakeba.dll" />
             <Payload Id="UnscheduledPackage.wxs" SourceFile="$(sys.SOURCEFILEDIR)UnscheduledPackage.wxs" Name="BootstrapperApplicationData.xml" />
-            <Payload Id="UnscheduledRollbackBoundary.wxs" SourceFile="$(sys.SOURCEFILEDIR)UnscheduledRollbackBoundary.wxs" Name="BundleExtensionData.xml" />
+            <Payload Id="UnscheduledRollbackBoundary.wxs" SourceFile="$(sys.SOURCEFILEDIR)UnscheduledRollbackBoundary.wxs" Name="BootstrapperExtensionData.xml" />
         </PayloadGroup>
     </Fragment>
 
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleExtension/BundleExtension.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BootstrapperExtension/BootstrapperExtension.wxs
index eefae822..8a422ad0 100644
--- a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleExtension/BundleExtension.wxs
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BootstrapperExtension/BootstrapperExtension.wxs
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
     <Fragment>
-        <BundleExtension Id="ExampleBext" SourceFile="fakeba.dll" Name="fakebext.dll" />
+        <BootstrapperExtension Id="ExampleBext" SourceFile="fakeba.dll" Name="fakebext.dll" />
     </Fragment>
 </Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleExtension/BundleExtensionSearches.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BootstrapperExtension/BootstrapperExtensionSearches.wxs
index fd8d3698..fd8d3698 100644
--- a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleExtension/BundleExtensionSearches.wxs
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BootstrapperExtension/BootstrapperExtensionSearches.wxs
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleExtension/BundleWithSearches.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BootstrapperExtension/BundleWithSearches.wxs
index d543c800..d543c800 100644
--- a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleExtension/BundleWithSearches.wxs
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BootstrapperExtension/BundleWithSearches.wxs
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleExtension/SimpleBundleExtension.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BootstrapperExtension/SimpleBootstrapperExtension.wxs
index 7303a05a..3af8c62c 100644
--- a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleExtension/SimpleBundleExtension.wxs
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BootstrapperExtension/SimpleBootstrapperExtension.wxs
@@ -5,6 +5,6 @@
             <PackageGroupRef Id="MinimalPackageGroup" />
         </PackageGroup>
 
-        <BundleExtensionRef Id="ExampleBext" />
+        <BootstrapperExtensionRef Id="ExampleBext" />
     </Fragment>
 </Wix>
diff --git a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleCustomTable/BundleCustomTable.wxs b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleCustomTable/BundleCustomTable.wxs
index e52302d4..4e6dfe62 100644
--- a/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleCustomTable/BundleCustomTable.wxs
+++ b/src/wix/test/WixToolsetTest.CoreIntegration/TestData/BundleCustomTable/BundleCustomTable.wxs
@@ -48,6 +48,6 @@
             </BundleElement>
         </BundleCustomDataRef>
 
-        <BundleExtension Id="CustomTableExtension" SourceFile="fakeba.dll" Name="fakebext.dll" />
+        <BootstrapperExtension Id="CustomTableExtension" SourceFile="fakeba.dll" Name="fakebext.dll" />
     </Fragment>
 </Wix>