$ git clone -n https://src.fedoraproject.org/rpms/deepin-wallpapers.git /var/lib/mock/f39-build-1545074-36675/root/chroot_tmpdir/scmroot/deepin-wallpapers
Cloning into '/var/lib/mock/f39-build-1545074-36675/root/chroot_tmpdir/scmroot/deepin-wallpapers'...
$ git fetch origin b16894eb14f6a83bc6609dbc4ac437b1f296d59a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/deepin-wallpapers
 * [new ref]         b16894eb14f6a83bc6609dbc4ac437b1f296d59a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b16894e Fix for new background filename