GNUZilla Icecat is a fully-free fork of Mozilla Firefox ESR. Extensions included to this version of IceCat: * LibreJS GNU LibreJS aims to address the JavaScript problem described in Richard Stallman's article The JavaScript Trap. * SpyBlock Blocks privacy trackers while in normal browsing mode, and all third party requests when in private browsing mode. Based on Adblock Plus. * AboutIceCat Adds a custom "about:icecat" homepage with links to information about the free software and privacy features in IceCat, and check-boxes to enable and disable the ones more prone to break websites. * HTML5-video-everywhere Uses the native video player to play embedded videos from different sources * Fingerprinting countermeasures: Fingerprinting is a series of techniques allowing to uniquely identify a browser based on specific characteristics of that particular instance . Unlike cookies the user cannot opt-out of being tracked this way, so the browser has to avoid giving away that kind of hints.