$ git clone -n https://src.fedoraproject.org/rpms/gnome-backgrounds.git /var/lib/mock/f40-build-2593113-62690/root/chroot_tmpdir/scmroot/gnome-backgrounds
Cloning into '/var/lib/mock/f40-build-2593113-62690/root/chroot_tmpdir/scmroot/gnome-backgrounds'...
$ git fetch origin e488c41104e14857f2085a9410adf7b15f6d4803:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnome-backgrounds
 * [new ref]         e488c41104e14857f2085a9410adf7b15f6d4803 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e488c41 Update to 46.0