$ git clone -n https://src.fedoraproject.org/rpms/trellis.git /var/lib/mock/f40-build-2170923-51033/root/chroot_tmpdir/scmroot/trellis
Cloning into '/var/lib/mock/f40-build-2170923-51033/root/chroot_tmpdir/scmroot/trellis'...
$ git fetch origin a56e6d4ffff878477ab28c5c3a8a424cb00be154:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/trellis
 * [new ref]         a56e6d4ffff878477ab28c5c3a8a424cb00be154 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a56e6d4 update to newer snapshot