$ git clone -n https://src.fedoraproject.org/rpms/OpenSceneGraph.git /var/lib/mock/f40-build-773880-127462/root/chroot_tmpdir/scmroot/OpenSceneGraph
Cloning into '/var/lib/mock/f40-build-773880-127462/root/chroot_tmpdir/scmroot/OpenSceneGraph'...
$ git fetch origin 789e47ad4492834b940b9dda8113a64c25ce7a8c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/OpenSceneGraph
 * [new ref]         789e47ad4492834b940b9dda8113a64c25ce7a8c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 789e47a Rebuild (jasper)