[DorothySim]

> What I'd really like to see is a JS implementation of the "dynamic" features like diffing

That's possible. I've made something like that (dynamically fetching git info via dump HTTP server protocol) using Git.js [0] although for a different reason and it worked very well. Some caveats: the decompression must be handled in a WebWorker or the UI is stuck pretty easily. But objects can be fetched on demand so it's kind of like Microsoft's Git Virtual FS. As you've said cross origin policies apply so either have the viewer on the same site as repos or add appropriate CORS headers.

[0]: https://github.com/yonran/git.js

I see git.js even has a "repo-viewer" demo [1]. Although it's very primitive it shows the ref list and diffs.

[1]: https://github.com/yonran/git.js/blob/master/demos/repo-view...