$ git clone -n https://src.fedoraproject.org/rpms/plasma-workspace.git /var/lib/mock/f42-build-side-1-3583022-46887/root/chroot_tmpdir/scmroot/plasma-workspace
Cloning into '/var/lib/mock/f42-build-side-1-3583022-46887/root/chroot_tmpdir/scmroot/plasma-workspace'...
$ git fetch origin a414114aac7ca91dda964a6deafceb094faa8963:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plasma-workspace
 * [new ref]         a414114aac7ca91dda964a6deafceb094faa8963 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a414114 6.4.2