$ git clone -n https://src.fedoraproject.org/rpms/f25-backgrounds.git /var/lib/mock/f40-build-1898639-25070/root/chroot_tmpdir/scmroot/f25-backgrounds
Cloning into '/var/lib/mock/f40-build-1898639-25070/root/chroot_tmpdir/scmroot/f25-backgrounds'...
$ git fetch origin 3374c3ca79b5dccca8d94c793162a886e7e4f63f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/f25-backgrounds
 * [new ref]         3374c3ca79b5dccca8d94c793162a886e7e4f63f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3374c3c Rebuilt for https://fedoraproject.org/wiki/Fedora_40_Mass_Rebuild