Under3 by codecivil

This trivial extension simply blocks all third party requests, thus ensuring that user browsing data are not transferred to any third party. Webpages displayed in this way may lack some functionality the user can now identify as a third party service.

So, under3 is a complement to fei, an addon targeted at users interested in the "size" of the internet's privacy problem without interfering with the browsing, giving users the experience of how the internet looks like without privacy leaks.

A more granular approach to this would be to adapt the firefox privacy settings or install and configure NoScript or some other add-on with similar scope.

"Under3" is the verbatim translation of the german phrase "unter 3" meaning "off the record".