I'm not the GP commenter, but I'm supposing there would be some way of announcing the git repo where you can find the source -- similar to the `<link...>` tag used for RSS, you could have a

  <link rel="alternate" type="application/x-git" title="my blog as a git repo" href="..." />

..and tooling could take care of all the things you like in an RSS reader. I could see this working really well for static site generators like vitepress or Jekyll or what have you, but going beyond what's in the source is kind of project-specific, but maybe I'm interested in just a summary of commits/PRs

Anyway, there isn't an official IANA-defined type for a git repo (the application/x-git is my closest guess until one became official) but my point is it isn't too far beyond what auto-discovery of RSS is.

I think the GP's comment is from the point of view of making it easy to retrieve the contents of the blog archive, easier than the hoops mentioned (bulk archive retrieval and generating WordPress page sequences, etc.) as well as solving the problem in TFA (partial feeds, partial blog contents in the feed).