CMake/Help/variable/CMAKE_PARENT_LIST_FILE.rst

CMAKE_PARENT_LIST_FILE
----------------------

Full path to the CMake file that included the current one.

While processing a CMake file loaded by include() or find_package()
this variable contains the full path to the file including it.  The
top of the include stack is always the CMakeLists.txt for the current
directory.  See also CMAKE_CURRENT_LIST_FILE.