$ git clone -n https://src.fedoraproject.org/rpms/f29-backgrounds.git /var/lib/mock/f40-build-2347011-60081/root/chroot_tmpdir/scmroot/f29-backgrounds
Cloning into '/var/lib/mock/f40-build-2347011-60081/root/chroot_tmpdir/scmroot/f29-backgrounds'...
$ git fetch origin 24fda51fe5ed0318e389ae429d6d280828a52c23:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/f29-backgrounds
 * [new ref]         24fda51fe5ed0318e389ae429d6d280828a52c23 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 24fda51 Rebuilt for https://fedoraproject.org/wiki/Fedora_40_Mass_Rebuild