$ git clone -n https://src.fedoraproject.org/rpms/plasma-discover.git /var/lib/mock/f42-bootstrap-3533866-46421/root/chroot_tmpdir/scmroot/plasma-discover
Cloning into '/var/lib/mock/f42-bootstrap-3533866-46421/root/chroot_tmpdir/scmroot/plasma-discover'...
$ git fetch origin 83a80be8620dc141208e12606f91dd30cec75d22:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plasma-discover
 * [new ref]         83a80be8620dc141208e12606f91dd30cec75d22 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 83a80be 6.3.5