$ git clone -n https://src.fedoraproject.org/rpms/f35-backgrounds.git /var/lib/mock/f39-build-1461986-33295/root/chroot_tmpdir/scmroot/f35-backgrounds
Cloning into '/var/lib/mock/f39-build-1461986-33295/root/chroot_tmpdir/scmroot/f35-backgrounds'...
$ git fetch origin 86d82f0aea80242a44867b244ebff3b7142d37ab:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/f35-backgrounds
 * [new ref]         86d82f0aea80242a44867b244ebff3b7142d37ab -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 86d82f0 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild