GNUzilla is the GNU version of the Mozilla suite, and GNU IceCat is the GNU version of the Firefox browser. Its main advantage is an ethical one: it is entirely free software. While the Firefox source code from the Mozilla project is free software, they distribute and recommend nonfree software as plug-ins and addons. Also their trademark license imposes requirements for the distribution of modified versions that make it inconvenient to exercise freedom 3.

Privacy protection features:

• LibreJS: GNU LibreJS aims to address the JavaScript problem described in Richard Stallman’s article The JavaScript Trap我們提供了兩個 ISO 映像：一個是當前的，一個是之前的（用於備份/穩定目的）。 ISO 是根據發布日期命名的。
• Https-Everywhere: Extension that encrypts your communications with many major websites, making your browsing more secure.
• 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 checkboxes to enable and disable the ones more prone to break websites.
• Fingerprinting countermeasures: Fingerprinting is a series of techniques allowing to uniquely identify a browser based on specific characterisics of that particular instance (like what fonts are available in that machine). Unlike cookies, the user cannot opt-out of being tracked this way; so the browser has to avoid giving away these kinds of hints.