$ git clone -n https://src.fedoraproject.org/rpms/plasma-workspace.git /var/lib/mock/f42-build-side-1-3566291-46733/root/chroot_tmpdir/scmroot/plasma-workspace
Cloning into '/var/lib/mock/f42-build-side-1-3566291-46733/root/chroot_tmpdir/scmroot/plasma-workspace'...
$ git fetch origin 705a591a31c846511fac559a5e184604e8034428:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plasma-workspace
 * [new ref]         705a591a31c846511fac559a5e184604e8034428 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 705a591 6.4.0