$ git clone -n https://src.fedoraproject.org/rpms/mate-backgrounds.git /var/lib/mock/f45-build-18050-507/root/chroot_tmpdir/scmroot/mate-backgrounds
Cloning into '/var/lib/mock/f45-build-18050-507/root/chroot_tmpdir/scmroot/mate-backgrounds'...
$ git fetch origin 0d3a4f5580f99c2a88f20a7eff4f837c9618d832:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mate-backgrounds
 * [new ref]         0d3a4f5580f99c2a88f20a7eff4f837c9618d832 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0d3a4f5 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild