$ git clone -n https://src.fedoraproject.org/rpms/astrometry-tycho2.git /var/lib/mock/f41-build-side-1-2810983-32924/root/chroot_tmpdir/scmroot/astrometry-tycho2
Cloning into '/var/lib/mock/f41-build-side-1-2810983-32924/root/chroot_tmpdir/scmroot/astrometry-tycho2'...
$ git fetch origin c253e51da0059bc17ba8c55090946a45d04ce323:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/astrometry-tycho2
 * [new ref]         c253e51da0059bc17ba8c55090946a45d04ce323 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c253e51 Index files moved within main astrometry package