The experiment has ended and the results have been good.

libcxx/include/CMakeLists.txt

@@ -1029,6 +1029,7 @@ set(files
   mdspan
   memory
   memory_resource
+  meta
   mutex
   new
   numbers

libcxx/include/module.modulemap.in

@@ -1683,6 +1683,11 @@ module std [system] {
     export *
   }
 
+  module meta {
+    header "meta"
+    export "*"
+  }
+
   module mutex {
     module lock_guard     { header "__mutex/lock_guard.h" }
     module mutex          { header "__mutex/mutex.h" }