$ git clone -n https://github.com/xcp-ng-rpms/iperf3 /var/lib/mock/v8.3-incoming-10651-29204/root/chroot_tmpdir/scmroot/iperf3
Cloning into '/var/lib/mock/v8.3-incoming-10651-29204/root/chroot_tmpdir/scmroot/iperf3'...
$ git fetch origin be3569db9a1e69cd6dba58798c91299c97752936:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/iperf3
 * [new ref]         be3569db9a1e69cd6dba58798c91299c97752936 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at be3569d Merge pull request #2 from xcp-ng-rpms/pcoval/review/master