Experimental: recycle the `import std` UUID

Now that GCC is supported, update the feature UUID.
diff --git a/Help/dev/experimental.rst b/Help/dev/experimental.rst
index 6f02744..dd12492 100644
--- a/Help/dev/experimental.rst
+++ b/Help/dev/experimental.rst
@@ -81,7 +81,7 @@
 set
 
 * variable ``CMAKE_EXPERIMENTAL_CXX_IMPORT_STD`` to
-* value ``0e5b6991-d74f-4b3d-a41c-cf096e0b2508``.
+* value ``a9e1cf81-9932-4810-974b-6eccaf14e457``.
 
 This UUID may change in future versions of CMake.  Be sure to use the value
 documented here by the source tree of the version of CMake with which you are
diff --git a/Source/cmExperimental.cxx b/Source/cmExperimental.cxx
index f6afc94..28919f8 100644
--- a/Source/cmExperimental.cxx
+++ b/Source/cmExperimental.cxx
@@ -39,7 +39,7 @@
     false },
   // CxxImportStd
   { "CxxImportStd",
-    "0e5b6991-d74f-4b3d-a41c-cf096e0b2508",
+    "a9e1cf81-9932-4810-974b-6eccaf14e457",
     "CMAKE_EXPERIMENTAL_CXX_IMPORT_STD",
     "CMake's support for `import std;` in C++23 and newer is experimental. It "
     "is meant only for experimentation and feedback to CMake developers.",
diff --git a/Tests/RunCMake/CXXModules/examples/import-std-export-no-std-build/CMakeLists.txt b/Tests/RunCMake/CXXModules/examples/import-std-export-no-std-build/CMakeLists.txt
index 89350ef..5d41b0e 100644
--- a/Tests/RunCMake/CXXModules/examples/import-std-export-no-std-build/CMakeLists.txt
+++ b/Tests/RunCMake/CXXModules/examples/import-std-export-no-std-build/CMakeLists.txt
@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "0e5b6991-d74f-4b3d-a41c-cf096e0b2508")
+  "a9e1cf81-9932-4810-974b-6eccaf14e457")
 
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_export_no_std CXX)
diff --git a/Tests/RunCMake/CXXModules/examples/import-std-export-no-std-install/CMakeLists.txt b/Tests/RunCMake/CXXModules/examples/import-std-export-no-std-install/CMakeLists.txt
index 62d9d91..fccb8b4 100644
--- a/Tests/RunCMake/CXXModules/examples/import-std-export-no-std-install/CMakeLists.txt
+++ b/Tests/RunCMake/CXXModules/examples/import-std-export-no-std-install/CMakeLists.txt
@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "0e5b6991-d74f-4b3d-a41c-cf096e0b2508")
+  "a9e1cf81-9932-4810-974b-6eccaf14e457")
 
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_export_no_std CXX)
diff --git a/Tests/RunCMake/CXXModules/examples/import-std-no-std-property/CMakeLists.txt b/Tests/RunCMake/CXXModules/examples/import-std-no-std-property/CMakeLists.txt
index a605e95..f21da1e 100644
--- a/Tests/RunCMake/CXXModules/examples/import-std-no-std-property/CMakeLists.txt
+++ b/Tests/RunCMake/CXXModules/examples/import-std-no-std-property/CMakeLists.txt
@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "0e5b6991-d74f-4b3d-a41c-cf096e0b2508")
+  "a9e1cf81-9932-4810-974b-6eccaf14e457")
 
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_no_std_property CXX)
diff --git a/Tests/RunCMake/CXXModules/examples/import-std-not-in-export-build/CMakeLists.txt b/Tests/RunCMake/CXXModules/examples/import-std-not-in-export-build/CMakeLists.txt
index 3112002..e3e11d1 100644
--- a/Tests/RunCMake/CXXModules/examples/import-std-not-in-export-build/CMakeLists.txt
+++ b/Tests/RunCMake/CXXModules/examples/import-std-not-in-export-build/CMakeLists.txt
@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "0e5b6991-d74f-4b3d-a41c-cf096e0b2508")
+  "a9e1cf81-9932-4810-974b-6eccaf14e457")
 
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_not_in_export CXX)
diff --git a/Tests/RunCMake/CXXModules/examples/import-std-not-in-export-install/CMakeLists.txt b/Tests/RunCMake/CXXModules/examples/import-std-not-in-export-install/CMakeLists.txt
index 788ea84..53ef333 100644
--- a/Tests/RunCMake/CXXModules/examples/import-std-not-in-export-install/CMakeLists.txt
+++ b/Tests/RunCMake/CXXModules/examples/import-std-not-in-export-install/CMakeLists.txt
@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "0e5b6991-d74f-4b3d-a41c-cf096e0b2508")
+  "a9e1cf81-9932-4810-974b-6eccaf14e457")
 
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_not_in_export CXX)
diff --git a/Tests/RunCMake/CXXModules/examples/import-std-transitive/CMakeLists.txt b/Tests/RunCMake/CXXModules/examples/import-std-transitive/CMakeLists.txt
index 4d1d5df..2f12662 100644
--- a/Tests/RunCMake/CXXModules/examples/import-std-transitive/CMakeLists.txt
+++ b/Tests/RunCMake/CXXModules/examples/import-std-transitive/CMakeLists.txt
@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "0e5b6991-d74f-4b3d-a41c-cf096e0b2508")
+  "a9e1cf81-9932-4810-974b-6eccaf14e457")
 
 cmake_minimum_required(VERSION 3.29)
 
diff --git a/Tests/RunCMake/CXXModules/examples/import-std/CMakeLists.txt b/Tests/RunCMake/CXXModules/examples/import-std/CMakeLists.txt
index bffcd66..95b6636 100644
--- a/Tests/RunCMake/CXXModules/examples/import-std/CMakeLists.txt
+++ b/Tests/RunCMake/CXXModules/examples/import-std/CMakeLists.txt
@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "0e5b6991-d74f-4b3d-a41c-cf096e0b2508")
+  "a9e1cf81-9932-4810-974b-6eccaf14e457")
 
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std CXX)
diff --git a/Tests/RunCMake/cmake_language/Experimental/CxxImportStd-set.cmake b/Tests/RunCMake/cmake_language/Experimental/CxxImportStd-set.cmake
index a002297..4a9edf4 100644
--- a/Tests/RunCMake/cmake_language/Experimental/CxxImportStd-set.cmake
+++ b/Tests/RunCMake/cmake_language/Experimental/CxxImportStd-set.cmake
@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "0e5b6991-d74f-4b3d-a41c-cf096e0b2508")
+  "a9e1cf81-9932-4810-974b-6eccaf14e457")
 
 cmake_language(GET_EXPERIMENTAL_FEATURE_ENABLED
   "CxxImportStd"