$ git clone -n https://src.fedoraproject.org/rpms/gxmms2.git /var/lib/mock/f45-build-13343-449/root/chroot_tmpdir/scmroot/gxmms2
Cloning into '/var/lib/mock/f45-build-13343-449/root/chroot_tmpdir/scmroot/gxmms2'...
$ git fetch origin ce14da81134cf6104e2495997715c8578293d160:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gxmms2
 * [new ref]         ce14da81134cf6104e2495997715c8578293d160 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ce14da8 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild