[whatwg] "Content-Disposition" property for <a> tags

[Michal Zalewski]

> On Linux you may have comprehensive mailcap lists in /etc, or better
> yet the filename extension to MIME type mappings used by httpds.

Which still don't necessarily map to the behavior of every single file
manager; some of them come with their own rules (heck, even mc does
that IIRC), some rely on /usr/bin/file. Plus, the solution needs to be
portable. It's really non-trivial, and the the current approach taken
by Firefox works only in rudimentary cases.

/mz