$ git clone -n https://src.fedoraproject.org/rpms/opencv.git /var/lib/mock/f40-build-2141103-50851/root/chroot_tmpdir/scmroot/opencv
Cloning into '/var/lib/mock/f40-build-2141103-50851/root/chroot_tmpdir/scmroot/opencv'...
$ git fetch origin 98cbcd26f408a460098eac516ca251d6b69b4925:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/opencv
 * [new ref]         98cbcd26f408a460098eac516ca251d6b69b4925 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 98cbcd2 Rebuild (gdal)