@Nicholas, Actually the data it mentions was accessible from the start, it is just informing the users now. The addon claims that it sends those data only to the installed desktop client. As the addon (and the desktop client) is not open-source, the users are in dark here and has to take Tonec on it's words. The least Tonec Inc. can do is let Mozilla audit their addon and get the trusted badge so that users can be sure their browsing habit isn't being sold to the highest bidder.