If you save webp images from the internet and you installed Chrome before a recent version of Firefox on Windows, our "save as" dialog will say "Chrome HTML Document (*.webp)". This is annoying and misleading.

We should probably just have localizable descriptions for some of the types we recognize ourselves, and stop relying on the registry for them. We already do this for PDFs, there's no particular reason we can't do the same for others, and make the code a bit more generic + use localized strings for them.

This affects all our desktop OSes, I think, though the example from comment #0 is from Windows.

I think the general mechanism for this should now be in place since bug 1639067 (part 2) landed.