GitHub has alternatives, but no replacement

Codeberg, a Git code hosting platform, recently took a decision to prohibit projects that mostly consist of generative-AI-written code which has prompted concern and extensive discussion elsewhere. The decision does not surprise me, and I don’t mean that as a criticism. Codeberg has always presented itself as a mission-driven alternative to GitHub, not neutral infrastructure.1 What interests me is the disappointment in the response. Many people reacted as though one of the few plausible GitHub replacements had ruled them or their projects out. They wanted Codeberg to be a universal alternative, a better GitHub and the obvious place to go when leaving it. To me, that exposes a big gap in the open-source space. There are plenty of places to host a Git repository, but remarkably few places to host an open-source community. GitHub gives projects a shared pool of identities, habits and paths to discovery. None of the alternatives has reproduced that at a similar scale.