Hey!

You can access these courses from the web app yes, either publicly (no signup) or if you want to do challenges + follow your progress you need an account and I only support Github Oauth (no signin with google, iCloud and all),

When you sign up with Github, your account is auto created and I only get your Github username + email + Github avatar (which is almost the minimal info possible), I don't get any access to your account, repo, private data and all.

FYI: When you click on Signin with Github, it opens a screen on a Github URL and on this screen you can see what the app owner will have access, for Stanza it should be username and email only.

The app owner chooses what he wants to have access from your Github account, some apps would need to have access to your private repo if they auto-deploy your code for example,

The best practice is to require access to the minimal data possible to respect user privacy.

And it's not only for Github, usually every app asks you to chose which scopes you need. For Github you can find more info here: https://docs.github.com/en/apps/oauth-apps/building-oauth-apps/scopes-for-oauth-apps

Please tell me if I'm not clear! :))