$ git clone -n https://src.fedoraproject.org/rpms/fedora-jam-backgrounds.git /var/lib/mock/f40-build-1996274-43999/root/chroot_tmpdir/scmroot/fedora-jam-backgrounds
Cloning into '/var/lib/mock/f40-build-1996274-43999/root/chroot_tmpdir/scmroot/fedora-jam-backgrounds'...
$ git fetch origin e1f0f814e63d6bb6791c8ad6165e52e206f05c15:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/fedora-jam-backgrounds
 * [new ref]         e1f0f814e63d6bb6791c8ad6165e52e206f05c15 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e1f0f81 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild