Some people talk about mailing lists with a lot of reverence, but I have only ever found them to be extremely ugly and unreadable.
Are there any good clients out there that make them readable? For example a lemmy-like, threaded interface with interactivity? Or for PR/MRs an interface that shows the diffs with syntax highlighting, toggleable unified and side by side diff views, ability to comment within diffs and continue discussions within them (maybe even threaded)?


If you hate having information delivered as text, you are never going to love mailing lists. They are not applications, and most likely never will be, since that would break the universal interoperability that makes email valuable.
However, email does support threading, and it is possible to find user agents (clients) that support it. Perhaps someone who has compared them recently can offer suggestions for whatever platform you use. (I can’t, since I’ve been using a proprietary one for ages and don’t know what else is out there these days.)
Also, you might find that some are better than others at formatting text to your liking.
Wdym? I’m reading text right now. We are interacting with text right now. It has formatting, has linking, has syntax highlighting, all depending on the client.
key: value object: key: valueAll this exists in lemmy and I love it.
A lot of other metadata exists in emails too:
Even reactions could be implemented via email e.g if the response body is a single emoji --> reaction.