@CoronaCoreanici Haha, I don't know! I've never played Go myself.
I use a library made by someone else for the chess ruleset: https://github.com/jhlywa/chess.js
Other than that, castling.club implements all the fediverse stuff, message formatting, drawing the board, and the detail pages you see at castling.club itself.
Server run by the main developers of the project It is not focused on any particular niche interest - everyone is welcome as long as you follow our code of conduct!