$ git clone -n https://src.fedoraproject.org/rpms/gn.git /var/lib/mock/f41-build-842734-161699/root/chroot_tmpdir/scmroot/gn
Cloning into '/var/lib/mock/f41-build-842734-161699/root/chroot_tmpdir/scmroot/gn'...
$ git fetch origin 0df6aee3cab2f5817c5fc661932f4b6d3c3f479f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gn
 * [new ref]         0df6aee3cab2f5817c5fc661932f4b6d3c3f479f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0df6aee Update to version 2185