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Official Iceweasel Icon, used in Debian Package - by Ricardo Fernandez Fuentes (Tri-licensed under Gnu GPL, Gnu LGPL, and Mozilla Public License)

What is Iceweasel?

Iceweasel is a fork [from Firefox] with the following purpose :

  1. backporting of security fixes to declared Debian stable version.

  2. no inclusion of trademarked Mozilla artwork (because of #1 above)

Beyond that, they will be basically identical. (quoting Roberto C. Sanchez post in debian-devel mailing list)

Firefox resumes distribution in Debian

As documented at the article The end of the Iceweasel Age, Firefox is now in Debian again with the official name and branding.

At Mozilla's request (see ?bug#815006), Debian now has Mozilla “Firefox ESR” (Extended Support Release) as the firefox-esr package. Normal Debian support policies, including patches for bug fixes, apply to the package.

How to install Iceweasel (Firefox)

In Debian Stretch and later, the package iceweasel is a transition to the firefox-esr package.

In Debian earlier than Stretch, the iceweasel package is a fork as described above. It can be installed from the Debian repository with

Localisation packages (such as iceweasel-l10n-fr) are also available.

Nevertheless a newer backport from the Debian Mozilla team is usually preferable. The Wikipedia explains some of the terminology.

How to get the Iceweasel branding on Firefox

The Mozilla add-on “Iceweasel Branding” applies the Debian Iceweasel branding to Firefox.

Currently (as of 2016-04-11) there is no Debian package to install that add-on.


The plugin directory is

while Debian-based xul-ext plugins can be found at

for more info on Iceweasel plugins, refer to the plugins section of the Mozilla page.

User-Agent string

Iceweasel's User-Agent strings are currently:

Some websites will serve different content depending on this string, or prevent access. You can change the User-Agent string manually (about:config, general.useragent.override preference) or via the User Agent Switcher plugin.

By default, general.useragent.compatMode.firefox is set to true, which includes "Firefox" in the User-Agent string.

Debian-Mozilla site

This is a resource where you can get the latest Iceweasel release which would eventually make it way into Debian's experimental, unstable and finally to testing and then stable. Usually the releases make their way to Debian unstable and then go downwards while the beta versions are released to experimental. Most of the aurora releases can be found at the repo.

You can also connect with the Debian-mozilla maintainers via the mailing list as well as on IRC via #debian-mozilla on

SSL / Secure Connection warning

The message

Can be disabled. see :

Customizing the default profile

The files that are copied to ~/.mozilla/firefox/ when creating a new Iceweasel profile (when the browser is run the first time, or by using the -P command-line option) may be found in /etc/iceweasel/profile/. These files will populate the new profile with default settings, extensions and much more.



Iceweasel is consistently crashing on a website

    MOZILLA_DISABLE_PLUGINS=1 iceweasel -safe-mode

    mv ~/.mozilla/firefox/ ~/old_firefox
    iceweasel &

Unsupported Browser Error

No H.264 support in youtube

    # apt-get install gstreamer1.0-libav gstreamer1.0-plugins-good

See also