I would love to always see the initial browser version support existed on pages like: https://www.w3schools.com/tags/tag_ul.asp
This is merely to satisfy my curiosity and is likely to be a lot of work so I don't expect to see it, but I do think it would be a very slight improvement to the site.
edit:
https://www.w3schools.com/tags/tag_details.asp is an example of a page that does have the version information