$ git clone -n https://src.fedoraproject.org/rpms/mrtg.git /var/lib/mock/f41-build-772604-13506/root/chroot_tmpdir/scmroot/mrtg
Cloning into '/var/lib/mock/f41-build-772604-13506/root/chroot_tmpdir/scmroot/mrtg'...
$ git fetch origin 8f4fd3e46751827705dc78d752edd925c3176666:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mrtg
 * [new ref]         8f4fd3e46751827705dc78d752edd925c3176666 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8f4fd3e Eliminate use of obsolete %patchN syntax (#2283636)