@SuperDicq @nyx Eh? Which ones for example?

Specially as like extensions typically aren't a POSIX conformance issue, both for utilities and for C interfaces.

Like there's namespace limits for C interfaces (mostly allowed prefixes/suffixes, and posix_ being a reserved prefix).

And pretty much none of utilities, which is why new posix options require to make sure to not step on ones that are already defined in existing implementations or to have consent from those (reminds me of a recent question about adding getopt_long in POSIX because well… probably going to run out of possible short options at some point).