$ git clone -n https://src.fedoraproject.org/rpms/plasma-disks.git /var/lib/mock/f42-build-side-1-3505195-45989/root/chroot_tmpdir/scmroot/plasma-disks
Cloning into '/var/lib/mock/f42-build-side-1-3505195-45989/root/chroot_tmpdir/scmroot/plasma-disks'...
$ git fetch origin a21159a8c5eb44ef9c36fdd02ffd70be12ad80f2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plasma-disks
 * [new ref]         a21159a8c5eb44ef9c36fdd02ffd70be12ad80f2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a21159a 6.3.4