$ git clone -n https://src.fedoraproject.org/rpms/crystal-stacker.git /var/lib/mock/f45-build-7134-358/root/chroot_tmpdir/scmroot/crystal-stacker
Cloning into '/var/lib/mock/f45-build-7134-358/root/chroot_tmpdir/scmroot/crystal-stacker'...
$ git fetch origin 6c10ab10b98c0e2f7452bfa4b03fed41d09102d0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/crystal-stacker
 * [new ref]         6c10ab10b98c0e2f7452bfa4b03fed41d09102d0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6c10ab1 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild