Hey, thanks for trying out the game! The game was made in javascript. You can actually start running the game at https://vykri.com/gamedevjs/ and press f12 then click sources to see the source code. The part you're probably interested in is gamedevjs/js/main.js .
A brief overview is that the "Login to Twitch" button leads to https://id.twitch.tv/oauth2/authorize (which includes the clientId and permissions you want. I only need to read chat for this game, but if you're making a bot, you'll also probably want to include sending messages as well). Then, when they get redirected back to my site from logging in, the url parameters include the access_token which can be used to connect to the irc websocket wss://irc-ws.chat.twitch.tv:443 which will call the onmessage function whenever someone sends a message in chat.
Good luck with your twitch bot!