reproduce:
        # https://github.com/gourryinverse/linux/commit/b7d5dc2d24cff71c32c00feeb78dd5ea1902520e
        git remote add gourryinverse https://github.com/gourryinverse/linux
        git fetch --no-tags gourryinverse private_compression
        git checkout b7d5dc2d24cff71c32c00feeb78dd5ea1902520e
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        # pip install -r Documentation/sphinx/requirements.txt
        make htmldocs