$ git clone -n https://src.fedoraproject.org/rpms/xmessage.git /var/lib/mock/f45-build-38948-730/root/chroot_tmpdir/scmroot/xmessage
Cloning into '/var/lib/mock/f45-build-38948-730/root/chroot_tmpdir/scmroot/xmessage'...
$ git fetch origin 0606353be21ac3baa461102219bde6fe00e39d49:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xmessage
 * [new ref]         0606353be21ac3baa461102219bde6fe00e39d49 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0606353 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild