Hey Kouzeru, thanks for the invite!
It's not really an extension to XO-chip, it's already in the spec, it's just not been implemented by interpreters :) The only thing that isn't defined is the colour palette. I've been thinking about drafting a separate proposal for the palette, but I have yet to finish that.
I've joined the Discord server, but I don't normally use Discord much so I need a few pointers ;) I'm Timendus on Discord too. Hit me up!