Extras are the small handy features that ride along with the Moderation bot. There is no separate bot to invite: activate Moderation and Extras comes with it. Two features live here, auto reactions that react to messages for you, and an autoresponder that replies to trigger words.
React automatically in the channels you pick, by message type or keyword.
Reply with your own text whenever a message matches a trigger word.
Reactions not added, the autoresponder not firing, and emoji the bot cannot use.