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 non-free 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.
If you want to install icecat (GNU icecat) on your Debian, you can do it by following those steps.
*/opt/* folder if you want to install it system-wide (you will need to have root privilege) or in your home folder if you only want to install it for your current user.*/usr/share/applications/* if you want to install it system-wide (you will need to have root privilege) or in *.local/share/applications/* if you only want to install it for your current user.Creating a .desktop file for icecat
Here is an example of a .desktop file
[Desktop Entry]
Name=Icecat ''Your version''
Comment=Web Browser
GenericName=Web Browser
X-GNOME-FullName=Icecat ''Your version'' Web Browser
Exec=/path/to/icecat/icecat %u
Terminal=false
X-MultipleArgs=false
Type=Application
Icon=/path/to/icecat/browser/chrome/icons/default/default128.png
Categories=Network;WebBrowser;
MimeType=text/html;text/xml;application/xhtml+xml;application/xml;application/vnd.mozilla.xul+xml;application/rss+xml;application/rdf+xml;image/gif;image/jpeg;image/png;x-scheme-handler/http;x-scheme-handler/https;
StartupWMClass=Icecat
StartupNotify=true
Note: In the above .desktop file, you can replace ''Your verion'' with any choice of your text, preferably icecat version.