Modules/ and Templates/ are installed by devel/cmake-modules.

Not upstreamable.
--- CMakeLists.txt.orig
+++ CMakeLists.txt
@@ -605,7 +605,7 @@
 
   # Install script directories.
   install(
-    DIRECTORY Help Modules Templates
+    DIRECTORY Help
     DESTINATION ${CMAKE_DATA_DIR}
     FILE_PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ
     DIRECTORY_PERMISSIONS OWNER_READ OWNER_EXECUTE OWNER_WRITE