$ git clone -n https://src.fedoraproject.org/rpms/iperf3.git /var/lib/mock/f45-build-14191-457/root/chroot_tmpdir/scmroot/iperf3
Cloning into '/var/lib/mock/f45-build-14191-457/root/chroot_tmpdir/scmroot/iperf3'...
$ git fetch origin 164d71b79384f676fe2e8c35ea4a3225bc5ae741:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/iperf3
 * [new ref]         164d71b79384f676fe2e8c35ea4a3225bc5ae741 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 164d71b Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild