I’ve wondered for a while, how does mutt work for HTML-formatted email and other MIME types? I compose my own emails with plain text, but plenty of my colleagues as well as the various mailing lists, official emails, and other services that I receive communications with use email which looks like a web page, and I can’t really give that up.
Nobody stops you from sending text/markdown MIME type. It wouldn't even be hard to render both HTML and plaintext from markdown. "Just do it"
The hard part is to fix anything in most common e-mail clients, let alone add something new. One example being Thunderbird - notoriously stale tickets, undocumented codebase and nearly impossible to get anything merged.
What I do is have HTML messages piped through 'w3m --dump'. 99% of the time this results in a usable representation of the message. The other one percent of the time, it's just another couple of keystrokes to load the content in your web browser.
By default I use lynx, which is a bit better than w3m with some content (might be my config), otherwise I have a keystroke to load the message in firefox, but with newsletter adding "view in browser button" more and more, I nearly never use it.
