You are speaking about release archives. GitHub's "Download as zip" feature is not the same thing as this multi decade-history of open source thing you are talk

You are speaking about release archives. GitHub's "Download as zip" feature is not the same thing as this multi decade-history of open source thing you are talking about. I always thought zip archives from this feature was generated on the fly, maybe cached, because I don't expect GitHub to store zip archive for every commit of every repository. I'm actually surprised many important projects are relying on a stable output from this feature, and that this output was actually stable.