$ git clone -n https://src.fedoraproject.org/rpms/f34-backgrounds.git /var/lib/mock/f40-build-2355555-60304/root/chroot_tmpdir/scmroot/f34-backgrounds
Cloning into '/var/lib/mock/f40-build-2355555-60304/root/chroot_tmpdir/scmroot/f34-backgrounds'...
$ git fetch origin d31d874959f4fe6e6702554fcc792d37d9272f20:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/f34-backgrounds
 * [new ref]         d31d874959f4fe6e6702554fcc792d37d9272f20 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d31d874 Rebuilt for https://fedoraproject.org/wiki/Fedora_40_Mass_Rebuild