We prefer 990px containers where possible, so if you're using gitlab on a browser smaller than that it'll usually butt up against the edges.
Couple of questions about your issue:
1. Any pages this is particularly bad for? Some dense pages (e.g. Pipelines or side-by-side diffs) need all the width they can get
2. what screen size do you normally use?
3. In Settings > Preferences > Behaviour, are you using Fixed layout or Fluid? Fixed should give you left/right margins if your window is >1280px
4. Do you collapse the left/right sidebars? I usually keep them both collapsed which helps reduce the crowding. But since they are expanded by default this is not an ideal solution
I mean, different mime versions of the same content are a possibility to do this transition: Send both plaintext, HTML and markdown, and the receiver could choose to display markdown if he otherwise would display plain text.
To be honest, this won't come. Google is pushing AMP into mails, that's exactly the opposite direction.
"The AMP version of the message is embedded into the email as a new MIME part, in addition to the HTML and plaintext, ensuring compatibility across all mail clients"
From https://amp.dev/documentation/guides-and-tutorials/start/cre...