BlackBook80 v6 [Medio Ting]

If your goal is to find or play free math games hosted on GitHub:

For the actual platform, you should use their official site: Most Popular Free Games : Access titles like Birds v Robots and Tommy's Trek

The Mathsframe.github.io site is a "completely independent" platform from the main .co.uk domain. It offers over 3,000 free games that require no downloads or registration.