$ git clone -n https://src.fedoraproject.org/rpms/libzypp.git /var/lib/mock/f42-build-884417-186000/root/chroot_tmpdir/scmroot/libzypp
Cloning into '/var/lib/mock/f42-build-884417-186000/root/chroot_tmpdir/scmroot/libzypp'...
$ git fetch origin a690bfb37a7ac560e1321d52b7be22c014880db3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libzypp
 * [new ref]         a690bfb37a7ac560e1321d52b7be22c014880db3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a690bfb Rebuild for yaml-cpp 0.8