I suppose this started when I upgraded to KDE 4.9.5, but I just noticed it today.
In KDE's system settings, I have Firefox set as the default web browser. It worked fine before now. But now when I click on an http: or https: URL in some other application, KDE downloads the page to its local cache, then launches Firefox to open the local file. So my Firefox is opening a file such as file:///var/tmp/kdecache-q/krun/8144_0_ I don't think I've changed any settings that should affect this, and I don't know what to change to fix it.
