Man pages matching name gfs_rmdir in section 3:

gfs_rmdir.3.en	debian 11 / libgfarm-dev
gfs_rmdir.3.ja	debian 11 / libgfarm-dev
gfs_rmdir.3.en	debian 12 / libgfarm-dev
gfs_rmdir.3.ja	debian 12 / libgfarm-dev