Mozilla, You Fuckers 2015-08-20
I have FireFox set to "Never Check For Updates" and I also have "Update Add-Ons Automatically" disabled, and yet for some reason my machine just queried my DNS server for "versioncheck-bg.addons.mozilla.org". Seriously guys, stop fucking pushing broken updates on me!
Now that I have added that domain name to my block list, hopefully it should not be a problem anymore.