$ git clone -n https://github.com/xcp-ng-rpms/iperf3.git /var/lib/mock/v8.3-u-pcoval2-10035-28680/root/chroot_tmpdir/scmroot/iperf3
Cloning into '/var/lib/mock/v8.3-u-pcoval2-10035-28680/root/chroot_tmpdir/scmroot/iperf3'...
$ git fetch origin 9f3f5b1d224857cdf37caca1b678a90f705f8b58:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/iperf3
 * [new ref]         9f3f5b1d224857cdf37caca1b678a90f705f8b58 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9f3f5b1 bump release for test build