ContinuumLT
From ASSS Wiki
ContinuumLT, Continuum Level Tool, or Continuum Level / Lvz Tool is an open source map editor for SubSpace written in Java.
ContinuumLT is currently only supported under Windows, though people have had some success at running it under different flavors of Linux. Included among its developers is BaK, a co-creator of the original CLIT editor.