Caniuse: User-Agent Strings

[acornforth]

It would be super handy in the various compatibility charts if the on-hover popup could contain the User-Agent strings that exist for that version of the browser, or at least the parts of the UA string that all versions of that browser have in common, and don't share with any other browsers.
This would provide us with a one-stop shop for browser compatibility _and_ a reference for what substring to search in the UA when deciding which content to serve...

[Fyrd]

Browser-sniffing is generally a bad idea, I'd rather not have caniuse take a part in encouraging it.