Oh, I'd forgotten about Tlon. Well, I looked it up, and what he claims to retain is "a few thousand stars" and a "non-voting minority in tlon". I guess the latter could be valuable monetarily (in some hypothetical future in which urbit is successful, anyway).
Then there's address space, and my understanding is that he gave up control of his galaxies, which doesn't say anything about the stars and planets that were in them.
With a little spelunking in the old codebase, and inspection of the Azimuth contract, someone interested in the question could no doubt answer it with reasonable confidence.