Disconnect is a free (GPLv3) add-on. The add-on is available here: https://disconnect.me/
The source and license are available here: https://github.com/disconnectme/disconnect (I'm one of the Disconnect devs and, in case you have no idea what I'm talking about :-), I'm referring to this page: https://www.gnu.org/software/gnuzilla/addons.html.) -- http://gnuzilla.gnu.org
