Index: clang-tools-extra/test/CMakeLists.txt
===================================================================
--- clang-tools-extra/test/CMakeLists.txt
+++ clang-tools-extra/test/CMakeLists.txt
@@ -17,7 +17,6 @@
 
 llvm_canonicalize_cmake_booleans(
   CLANG_TIDY_ENABLE_STATIC_ANALYZER
-  LIBCLANG_INCLUDE_CLANG_TOOLS_EXTRA
   )
 
 configure_lit_site_cfg(
@@ -68,10 +67,6 @@
   # Clang-tidy tests need clang for building modules.
   clang
 )
-if (LIBCLANG_INCLUDE_CLANG_TOOLS_EXTRA)
-  # For the clang-tidy libclang integration test.
-  set(CLANG_TOOLS_TEST_DEPS ${CLANG_TOOLS_TEST_DEPS} "c-index-test")
-endif ()
 
 # Add lit test dependencies.
 set(LLVM_UTILS_DEPS
Index: clang-tools-extra/test/clang-tidy/infrastructure/nolint-plugin.cpp
===================================================================
--- clang-tools-extra/test/clang-tidy/infrastructure/nolint-plugin.cpp
+++ /dev/null
@@ -1,50 +0,0 @@
-// REQUIRES: static-analyzer, libclang_include_clang_tools_extra
-// RUN: c-index-test -test-load-source-reparse 2 all %s -Xclang -add-plugin -Xclang clang-tidy -Xclang -plugin-arg-clang-tidy -Xclang -checks='-*,google-explicit-constructor,clang-diagnostic-unused-variable,clang-analyzer-core.UndefinedBinaryOperatorResult' -Wunused-variable -I%S/Inputs/nolint 2>&1 | FileCheck %s
-
-#include "trigger_warning.h"
-void I(int& Out) {
-  int In;
-  A1(In, Out);
-}
-// CHECK-NOT: trigger_warning.h:{{.*}} warning
-// CHECK-NOT: :[[@LINE-4]]:{{.*}} note
-
-class A { A(int i); };
-// CHECK-DAG: :[[@LINE-1]]:11: warning: single-argument constructors must be marked explicit
-
-class B { B(int i); }; // NOLINT
-
-class C { C(int i); }; // NOLINT(for-some-other-check)
-// CHECK-DAG: :[[@LINE-1]]:11: warning: single-argument constructors must be marked explicit
-
-class C1 { C1(int i); }; // NOLINT(*)
-
-class C2 { C2(int i); }; // NOLINT(not-closed-bracket-is-treated-as-skip-all
-
-class C3 { C3(int i); }; // NOLINT(google-explicit-constructor)
-
-class C4 { C4(int i); }; // NOLINT(some-check, google-explicit-constructor)
-
-class C5 { C5(int i); }; // NOLINT without-brackets-skip-all, another-check
-
-void f() {
-  int i;
-// CHECK-DAG: :[[@LINE-1]]:7: warning: unused variable 'i' [-Wunused-variable]
-//                          31:7: warning: unused variable 'i' [-Wunused-variable]
-//  int j; // NOLINT
-//  int k; // NOLINT(clang-diagnostic-unused-variable)
-}
-
-#define MACRO(X) class X { X(int i); };
-MACRO(D)
-// CHECK-DAG: :[[@LINE-1]]:7: warning: single-argument constructors must be marked explicit
-MACRO(E) // NOLINT
-
-#define MACRO_NOARG class F { F(int i); };
-MACRO_NOARG // NOLINT
-
-#define MACRO_NOLINT class G { G(int i); }; // NOLINT
-MACRO_NOLINT
-
-#define DOUBLE_MACRO MACRO(H) // NOLINT
-DOUBLE_MACRO
Index: clang-tools-extra/test/clang-tidy/infrastructure/nolintnextline-plugin.cpp
===================================================================
--- clang-tools-extra/test/clang-tidy/infrastructure/nolintnextline-plugin.cpp
+++ /dev/null
@@ -1,49 +0,0 @@
-// REQUIRES: libclang_include_clang_tools_extra
-// RUN: c-index-test -test-load-source-reparse 2 all %s -Xclang -add-plugin -Xclang clang-tidy -Xclang -plugin-arg-clang-tidy -Xclang -checks='-*,google-explicit-constructor' 2>&1 | FileCheck %s
-
-class A { A(int i); };
-// CHECK: :[[@LINE-1]]:11: warning: single-argument constructors must be marked explicit
-
-// NOLINTNEXTLINE
-class B { B(int i); };
-
-// NOLINTNEXTLINE(for-some-other-check)
-class C { C(int i); };
-// CHECK: :[[@LINE-1]]:11: warning: single-argument constructors must be marked explicit
-
-// NOLINTNEXTLINE(*)
-class C1 { C1(int i); };
-
-// NOLINTNEXTLINE(not-closed-bracket-is-treated-as-skip-all
-class C2 { C2(int i); };
-
-// NOLINTNEXTLINE(google-explicit-constructor)
-class C3 { C3(int i); };
-
-// NOLINTNEXTLINE(some-check, google-explicit-constructor)
-class C4 { C4(int i); };
-
-// NOLINTNEXTLINE without-brackets-skip-all, another-check
-class C5 { C5(int i); };
-
-
-// NOLINTNEXTLINE
-
-class D { D(int i); };
-// CHECK: :[[@LINE-1]]:11: warning: single-argument constructors must be marked explicit
-
-// NOLINTNEXTLINE
-//
-class E { E(int i); };
-// CHECK: :[[@LINE-1]]:11: warning: single-argument constructors must be marked explicit
-
-#define MACRO(X) class X { X(int i); };
-MACRO(F)
-// CHECK: :[[@LINE-1]]:7: warning: single-argument constructors must be marked explicit
-// NOLINTNEXTLINE
-MACRO(G)
-
-#define MACRO_NOARG class H { H(int i); };
-// NOLINTNEXTLINE
-MACRO_NOARG
-
Index: clang-tools-extra/test/lit.site.cfg.py.in
===================================================================
--- clang-tools-extra/test/lit.site.cfg.py.in
+++ clang-tools-extra/test/lit.site.cfg.py.in
@@ -11,7 +11,6 @@
 config.python_executable = "@Python3_EXECUTABLE@"
 config.target_triple = "@TARGET_TRIPLE@"
 config.clang_tidy_staticanalyzer = @CLANG_TIDY_ENABLE_STATIC_ANALYZER@
-config.libclang_include_clang_tools_extra = @LIBCLANG_INCLUDE_CLANG_TOOLS_EXTRA@
 
 # Support substitution of the tools and libs dirs with user parameters. This is
 # used when we can't determine the tool dir at configuration time.
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -151,6 +151,10 @@
 These are major changes to the build system that have happened since the 12.0.0
 release of Clang. Users of the build system should adjust accordingly.
 
+- The option ``LIBCLANG_INCLUDE_CLANG_TOOLS_EXTRA`` no longer exists. There were
+  two releases with that flag forced off, and no uses were added that forced it
+  on.
+
 - ...
 
 AST Matchers
Index: clang/tools/libclang/CIndex.cpp
===================================================================
--- clang/tools/libclang/CIndex.cpp
+++ clang/tools/libclang/CIndex.cpp
@@ -9161,16 +9161,3 @@
     OS << "--------------------------------------------------\n";
   }
 }
-
-#ifdef CLANG_TOOL_EXTRA_BUILD
-// This anchor is used to force the linker to link the clang-tidy plugin.
-extern volatile int ClangTidyPluginAnchorSource;
-static int LLVM_ATTRIBUTE_UNUSED ClangTidyPluginAnchorDestination =
-    ClangTidyPluginAnchorSource;
-
-// This anchor is used to force the linker to link the clang-include-fixer
-// plugin.
-extern volatile int ClangIncludeFixerPluginAnchorSource;
-static int LLVM_ATTRIBUTE_UNUSED ClangIncludeFixerPluginAnchorDestination =
-    ClangIncludeFixerPluginAnchorSource;
-#endif
Index: clang/tools/libclang/CMakeLists.txt
===================================================================
--- clang/tools/libclang/CMakeLists.txt
+++ clang/tools/libclang/CMakeLists.txt
@@ -52,22 +52,6 @@
   list(APPEND LIBS clangARCMigrate)
 endif ()
 
-option(LIBCLANG_INCLUDE_CLANG_TOOLS_EXTRA
-  "Include code from clang-tools-extra in libclang." OFF)
-
-if (LIBCLANG_INCLUDE_CLANG_TOOLS_EXTRA)
-  if (TARGET clangTidyPlugin)
-    add_definitions(-DCLANG_TOOL_EXTRA_BUILD)
-    list(APPEND LIBS clangTidyPlugin)
-    list(APPEND LIBS clangIncludeFixerPlugin)
-    if(LLVM_ENABLE_MODULES)
-      list(APPEND LLVM_COMPILE_FLAGS "-fmodules-ignore-macro=CLANG_TOOL_EXTRA_BUILD")
-    endif()
-  else ()
-    message(FATAL_ERROR "LIBCLANG_INCLUDE_CLANG_TOOLS_EXTRA needs clang-tools-extra in LLVM_ENABLE_PROJECTS")
-  endif ()
-endif ()
-
 if (HAVE_LIBDL)
   list(APPEND LIBS ${CMAKE_DL_LIBS})
 elseif (CLANG_BUILT_STANDALONE)
Index: llvm/utils/gn/secondary/clang-tools-extra/test/BUILD.gn
===================================================================
--- llvm/utils/gn/secondary/clang-tools-extra/test/BUILD.gn
+++ llvm/utils/gn/secondary/clang-tools-extra/test/BUILD.gn
@@ -1,6 +1,5 @@
 import("//clang-tools-extra/clang-tidy/enable.gni")
 import("//clang/lib/StaticAnalyzer/Frontend/enable.gni")
-import("//clang/tools/libclang/include_clang_tools_extra.gni")
 import("//llvm/triples.gni")
 import("//llvm/utils/gn/build/write_cmake_config.gni")
 import("clang_tools_extra_lit_site_cfg_files.gni")
@@ -44,12 +43,6 @@
   } else {
     extra_values += [ "CLANG_TIDY_ENABLE_STATIC_ANALYZER=0" ]
   }
-
-  if (libclang_include_clang_tools_extra) {
-    extra_values += [ "LIBCLANG_INCLUDE_CLANG_TOOLS_EXTRA=1" ]
-  } else {
-    extra_values += [ "LIBCLANG_INCLUDE_CLANG_TOOLS_EXTRA=0" ]
-  }
 }
 
 write_lit_config("lit_unit_site_cfg") {
Index: llvm/utils/gn/secondary/clang/tools/libclang/BUILD.gn
===================================================================
--- llvm/utils/gn/secondary/clang/tools/libclang/BUILD.gn
+++ llvm/utils/gn/secondary/clang/tools/libclang/BUILD.gn
@@ -1,5 +1,4 @@
 import("//clang/lib/ARCMigrate/enable.gni")
-import("//clang/tools/libclang/include_clang_tools_extra.gni")
 import("//llvm/version.gni")
 
 # This build file is just enough to get check-clang to pass, it's missing
@@ -40,16 +39,6 @@
 
   defines = []
 
-  # FIXME: Once the GN build has a way to select which bits to build,
-  # only include this dependency if clang-tools-extra is part of the build.
-  if (libclang_include_clang_tools_extra) {
-    defines += [ "CLANG_TOOL_EXTRA_BUILD" ]
-    deps += [
-      "//clang-tools-extra/clang-include-fixer/plugin",
-      "//clang-tools-extra/clang-tidy/plugin",
-    ]
-  }
-
   if (host_os == "win") {
     defines += [ "_CINDEX_LIB_" ]
   }
Index: llvm/utils/gn/secondary/clang/tools/libclang/include_clang_tools_extra.gni
===================================================================
--- llvm/utils/gn/secondary/clang/tools/libclang/include_clang_tools_extra.gni
+++ /dev/null
@@ -1,4 +0,0 @@
-declare_args() {
-  # Whether to include code from clang-tools-extra in libclang.
-  libclang_include_clang_tools_extra = false
-}