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.
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