I believe what you saw was a promotion of https://addons.mozilla.org/en-US/firefox/addon/facebook-container/ https://addons.mozilla.org/en-US/firefox/addon/face

I believe what you saw was a promotion of https://addons.mozilla.org/en-US/firefox/addon/facebook-container/ https://addons.mozilla.org/en-US/firefox/addon/facebook-cont... That extension is described as: "Prevent Facebook from tracking you around the web. The Facebook Container extension for Firefox helps you take control and isolate your web activity from Facebook."