Well, according to (ahem) a copy that I found, it only goes up to MRI 1.9 and goes out of its way to say "welp, the world is changing, so we're just going to punt until Ruby stabilizes" which is damn cheating for a standard IMHO

Also, while doing some digging I found there actually are a number of the standards that are legitimately publicly available https://standards.iso.org/ittf/PubliclyAvailableStandards/in...

ISO Ruby is a tiny, dated subset of Ruby. I doubt you'll find much Ruby that conforms to it.

The Ruby everyone uses is much better defined by RubySpec etc. via test cases, but that's not complete either.