$ git clone -n https://src.fedoraproject.org/rpms/mate-backgrounds.git /var/lib/mock/f40-build-2703024-70754/root/chroot_tmpdir/scmroot/mate-backgrounds
Cloning into '/var/lib/mock/f40-build-2703024-70754/root/chroot_tmpdir/scmroot/mate-backgrounds'...
$ git fetch origin 339ae07b39dc629faf14a2fc9d84f9fc0c58b238:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mate-backgrounds
 * [new ref]         339ae07b39dc629faf14a2fc9d84f9fc0c58b238 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 339ae07 update to 1.28.0