$ git clone -n https://src.fedoraproject.org/rpms/f34-backgrounds.git /var/lib/mock/f40-build-2362317-60364/root/chroot_tmpdir/scmroot/f34-backgrounds
Cloning into '/var/lib/mock/f40-build-2362317-60364/root/chroot_tmpdir/scmroot/f34-backgrounds'...
$ git fetch origin 117f4a5ae133dda063cb6bffcdbb2de8303749e2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/f34-backgrounds
 * [new ref]         117f4a5ae133dda063cb6bffcdbb2de8303749e2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 117f4a5 Rebuild with kde4-filesystem dependency