@sir tbh, IRC is not that good a protocol. The core of it is pretty good, definitely better than a random proprietary JSON-over-websocket stuff. Bu ton top of that core, a lot of nasty things grew.
Everybody has extensions on top of RFC1459. RFC2811 contains some of those extensions, but also a lot of supposedly-standard features that never got implemented.
Then there's ISUPPORT, and some other stuff like that.
And I'm not even touching on upper layers like services or CTCP.
Basically, IRC is not standardized at all.
It's like "do whatever everyone else does".
Even the IRCv3 group (whose extensions are IMO pretty nice and well documented) didn't bother to standardize what they're extensions are built on top. They cite 1459, but that alone is not enough to get a working implementation.
I think in the IRC-dominated universe you mentioned, the protocol must've evolved in a different way.
Welcome to your niu world ! We are a cute and loving international community Ｏ(≧▽≦)Ｏ !