btw, cob had the issues of 3ds in not long names for material names, if I remember well. Also, an advantage (I always preferred it over 3ds) is it keeps quads. Depending on tool and exporter, it tends to keep material features and colors, and vertex colors, again, If am remembering well. Scn files where actual total support of the scenery, but also animation, etc. I suppose is very tied to the version of ts, in that format.And probably not much specs out there, as there are many plugins for cob, very few for scn.
Collada, for example, is so really much more complete. i even find easier to handle , and more problem free, more widely adopted, the OBJ format. Also, there are a few command line converters, majorly DOS-based , that converted COB 2 ‘whatever’. Sort of what image magik does for 2d. I dunno if is easier for you to launch those than a win32 app, or if, probably , already there are ports of those utilities to linux. There’s much probably more Linux modeling tools that can import cob and export to whatever.