It lists repositories that are published on nostr using NIP-34. In a NIP-34 repo you list one or more git servers where the code is hosted. Most people just linked it to GitHub.

Amethyst must have stored their nostr repo code on GitHub then.

The problem with using GitHub as a back-end is that people need pretty much kyc'd accounts to participate as a maintainer + each backend has its own user management.

Dan's new server fixed that with auth by nostr, meaning we can manage contributors more easily AND for example make pushes from the browser with just a nostr sign-in. (I want to enable pull-request views and merging here too)