$ git clone -n https://github.com/xcp-ng-rpms/iperf3.git /var/lib/mock/v8.3-u-pcoval2-10400-28961/root/chroot_tmpdir/scmroot/iperf3
Cloning into '/var/lib/mock/v8.3-u-pcoval2-10400-28961/root/chroot_tmpdir/scmroot/iperf3'...
$ git fetch origin 76701c826ef5569584684c7198e45a13dbac79eb:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/iperf3
 * [new ref]         76701c826ef5569584684c7198e45a13dbac79eb -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 76701c8 bump release for test build