In terms of IRC is functionally identical.
George already fed you the API notes.
Heres the chat/IRC notes https://dev.twitch.tv/docs/irc#twitch-irc-capability-chat-rooms
Main difference is that some commands like /clear don’t work. Tags work the same (room_id is streamerID not the full room ID though)
And yeah it’s a spruced up UI to “normal” users.