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GNU IceCat and the Free Software Directory

by Joshua Gay Contributions Published on Jul 08, 2015 04:51 PM

The GNU IceCat browser is part of GNUzilla, the GNU version of Mozilla's suite of software that includes the Firefox Web browser. IceCat is a browser designed to respect your privacy and your freedom.

When you first start up GNU IceCat, the default landing page is the about:icecat page. It provides seven checkboxes that allow you to enable privacy features including blocking non-free JavaScript and privacy trackers, or disabling JavaScript entirely, and redirecting to HTTPS whenever possible.

Under the hood, these options are implemented using several browser add-ons and extensions. GNU LibreJS blocks execution of nonfree JavaScript. Https-Everywhere encrypts your communications with many major Web sites, making your browsing more secure. SpyBlock and Adblock Plus block privacy trackers while in normal browsing mode, and all third party requests when in private browsing mode. Also, there are some important things you won't find under the hood, such as the proprietary Adobe Primetime add-on, which is based on the W3C draft specification for baking DRM into HTML5 via its Encrypted Media Extension1. GNU IceCat is committed to slamming shut and rooting out backdoors and other malware from Mozilla standard releases of Firefox.

GNU IceCat logo

In fact, GNU IceCat only recommends installing free software add-ons. In fact, IceCat has replaced the Mozilla add-ons search with GNU IceCat page from the FSF's Free Software Directory (FSD) -- which lists all of the IceCat add-ons that have been reviewed and added to the FSD so far, which, at this point in time isn't nearly as many as we would like, and not nearly as many as what Mozilla has listed on their addons site.

The majority of add-ons on the Mozilla Add-ons site are free software. As such, we were at first tempted to simply write a script that imported all of the Mozilla Add-ons with free software licenses listed into the FSD. However, after reviewing a sampling of add-ons by hand, we found that there was a fair number of add-ons that had incorrect licensing information listed, and in some cases the add-ons were, in fact, proprietary.

To solve this problem, Free Software Directory volunteers are making a concerted effort to add many more IceCat extensions to the FSD. Driving much of this work is David Hedlund, who has curated lists of hundreds of popular add-ons for our community of volunteers to review and hopefully add to the FSD. David's approach is creative. His top tier list is browser add-ons with over one million daily users, his second tier list have between 100k and 999k daily users, and so on. In addition to creating these lists, David has made over a thousand edits and has added many new packages and pages to the FSD over the past few months.

One interesting consequence of this work, and other work being done on the Free Software Directory, is that it doesn't just result in a bigger and better catalog of free software on the FSD. In their quest to add new entries to the FSD, contributors often end up submitting bug fixes or filing bug reports to other projects, to eliminate nonfree bugs that are preventing a package from being listed in the FSD. And when we add a new package to the FSD, we encourage FSD contributors to notify its maintainers. After all, one thing most free software developers agree upon (and there isn't much we agree upon!) is that it is nice to know others appreciate and show interest in the software we are making.

GNU IceCat add-ons are just one of the many ways we are improving the Free Software Directory on a day-to-day basis. If you are interested in learning more, visit to learn how to get started, or stop by IRC during our weekly Friday Free Software Directory IRC Meeting. See for details on the next meeting.

Special thanks to our FSD volunteers and contributors, as well as to Rubén Rodríguez for maintaining GNU IceCat and other important free software projects.

Finally, if you haven't done so already, download GNU IceCat2 now.


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