Comment 16 for bug 39136

This bug has been reported by Ubuntu users, at
 https://launchpad.net/distros/ubuntu/+source/firefox/+bug/39136

I investigated the code and the fundamental problem seems to be the use of
 mCategoryManager->GetCategoryEntry("Gecko-Content-Viewers",aContentType, )
throughout the code whenever we want to use the Gecko renderer for a type, or check that Gecko can handle it. It's tempting to replace all of these calls with a new function which would do the special handling of unknown text/* types. But I'm not sure that that's correct; in particular, it might make known external text/<something> types malfunction.

So, I'm not sure what needs to be done.

For the avoidance of doubt, I agree 100% with the reporters statement in comment 0, and with Brandon Hall's in comment 9.

Boris Zbarsky's comments that "All the common text/* types that we don't already render as text/plain are not something the user wants to see by default" is missng the point. Sites and applications are free to invent new text/x-* types and RFC2046 says that we should treat those as text/plain if we don't recognise them. Mozilla is never going to be able to have a complete list of these text/* types and it is futile to try. Instead, the logic as required by RFC2046 should be implemented.