Rated 1 out of 5 stars

Not sure if it's just a defect. I did not do any analysis to see if this extension sends traffic to any site, but it is anything but passive. Disabled it, restarted, and firefox is now well-behaved again. This is the plugin I installed most recently, so it was the first suspect.

64-bit Fedora 21, Firefox 38.0.5. If I try it again or perhaps find time to break out the network sniffer, I'll update this review.