Yeah I saw that it has an example. I didn’t see anything there suggesting it is a specification of all the metadata tags. It’s better than nothing though.
That document, documents all the meta that Twitch will be sending.
Twitch is taking parts of the IRCv3 specification which allows you to create your own additional data, so the meta that will be sent is documented in that document.
There is no other meta that will be send on the Twitch IRC network, if that is what you are expecting.