$ git clone -n https://src.fedoraproject.org/rpms/gdm.git /var/lib/mock/f40-build-2590932-62639/root/chroot_tmpdir/scmroot/gdm
Cloning into '/var/lib/mock/f40-build-2590932-62639/root/chroot_tmpdir/scmroot/gdm'...
$ git fetch origin 87b5f7b54d29d59b3e4946c94bbb59ab92bb96cb:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gdm
 * [new ref]         87b5f7b54d29d59b3e4946c94bbb59ab92bb96cb -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 87b5f7b Update to 46.0