$ git clone -n https://src.fedoraproject.org/rpms/plasma-systemmonitor.git /var/lib/mock/f42-build-side-1-3512251-46067/root/chroot_tmpdir/scmroot/plasma-systemmonitor
Cloning into '/var/lib/mock/f42-build-side-1-3512251-46067/root/chroot_tmpdir/scmroot/plasma-systemmonitor'...
$ git fetch origin 880fd7b00642bd913b9fa98d3e88d6a41688a2d3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plasma-systemmonitor
 * [new ref]         880fd7b00642bd913b9fa98d3e88d6a41688a2d3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 880fd7b 6.3.4