[Bug 62285] Re: cannot disable preview of postscript files

[Andreas Simon]

Yes, it's a hack from the time when there was no real inheritance in the
mime spec from freedesktop.org. KDE4 will use the new spec and this hack
will no longer be needed.

KDE needed this in cases when there is no specific mime handler
installed, but the mime type is (also) a text format, so that therefore
a text editor can be started. So they added a way to tell that foo/bar
is also text/plain. You find this also for example in all script types
like application/x-python.

Anyway, you are right in that it's currently somewhat inconsistent. I
dunno if it makes sense to add this to PDF too, I never heard of anyone
editing a PDF with a text editor, contrary to PS, but at least
encpsulated postscript should probably have this too.

-- 
cannot disable preview of postscript files
https://launchpad.net/bugs/62285