Firefox to add Tor Browser anti-fingerprinting technique called letterboxing
The Tor Uplift process later continued in Firefox 55 when Mozilla added a Tor Browser feature known as First-Party Isolation (FPI), which worked by separating cookies on a per-domain basis, preventing ad trackers from using cookies to track users across the Internet. This feature is now at the heart of Project Fission and will morph into a Chrome-like "site isolation" feature for Firefox.This is just factually incorrect.