>> Or did you mean how these processes handle evolving registries of
>> things? I don't know about that.
>
> Yes, I meant how these things are handled for specifications of other
> languages. Maybe we can steal a few ideas from there.

With a quick search, I can't find any such registries in a prior language.

Python PEP doesn't look like it has any: <https://www.python.org/dev/peps/>

Java JSR neither: <https://jcp.org/en/jsr/stage?listBy=final>

Common Lisp CDR not either: <https://common-lisp.net/project/cdr/>

A web search for these languages and "registry", "identifiers" or
"identifier registry" doesn't bring up anything useful.

So we're on our own unless anyone has any more leads.