$ git clone -n https://src.fedoraproject.org/rpms/grass.git /var/lib/mock/f42-build-863023-171338/root/chroot_tmpdir/scmroot/grass
Cloning into '/var/lib/mock/f42-build-863023-171338/root/chroot_tmpdir/scmroot/grass'...
$ git fetch origin d4715aa6a1075f1c5c9fa5209e5845a00e43cdd5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/grass
 * [new ref]         d4715aa6a1075f1c5c9fa5209e5845a00e43cdd5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d4715aa Rebuild (gdal)