$ git clone -n https://src.fedoraproject.org/rpms/constantine-backgrounds.git /var/lib/mock/f45-build-4651-333/root/chroot_tmpdir/scmroot/constantine-backgrounds
Cloning into '/var/lib/mock/f45-build-4651-333/root/chroot_tmpdir/scmroot/constantine-backgrounds'...
$ git fetch origin d1549b057eaff1fc13699a04e439341d4db83135:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/constantine-backgrounds
 * [new ref]         d1549b057eaff1fc13699a04e439341d4db83135 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d1549b0 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild