In Ubuntu 14.04, when I do a search in Firefox using either the address bar or the search bar, the system always adds t=canonical to my searches. So the full string becomes: https://duckduckgo.com/?q=cat+cooking+salmon&t=canonical.

However, if I perform the same search by going directly to the search engine, i.e. typing the search engine name and doing the search from the presented search box, this does not happen. In this case the string is: https://duckduckgo.com/?q=cat+cooking+salmon.

Search made directly by going to DuckDuckGo

How do I stop Ubuntu/Firefox from adding t=canonical to my search queries? And, why is this behavior there in the first place?

  • 4
    But wait! It gets better! This is a screenshot taken in Chrome, on a Mac. i.imgur.com/WbW2d1M.png
    – jrg
    Feb 27, 2015 at 14:28
  • 1
    So it gets infested across the entire ecosystem, and follows it from browser to browser, and platform to platform.
    – jrg
    Feb 27, 2015 at 14:33
  • 5
    Note that even if you remove this from the querystring, your browser is still broadcasting "Ubuntu" in the user-agent string.
    – Oli
    Feb 28, 2015 at 15:28
  • 2
    It is so hard to make money in "pure" Open Source. Why not support Ubuntu Linux in this small way?
    – lnostdal
    May 18, 2016 at 14:34
  • 3
    @lnostdal: "It is so hard to make money in "pure" Open Source. Why not support Ubuntu Linux in this small way?" --- Privacy, although I was more interested in learning the how/why.
    – Daniel
    May 18, 2016 at 20:41

6 Answers 6



Through partnerships with developers and companies, DuckDuckGo has been integrated into many applications. In these partnerships, a portion of DuckDuckGo's advertising revenue is sometimes shared back. To assign advertising revenue and collect anonymous aggregate usage information, developers add a unique "&t=" parameter to searches made through their applications.

If you want to remove it, edit the file:


Edit all the languages just to be sure.

enter image description here

Edit for 20.04

  1. Open Firefox, navigate to Preferences --> Search, and remove the per-installed DuckDuckGo search engine
  2. Download the search engine new from the Firefox Add-ons directory. Select this as the default search engine in the preferences The string, &t=canonícal, ceased to insert itself into the searches via the address bar thereafter. With help from Komalleana Byzantis

Below are before and after pictures:

enter image description here

enter image description here

Source:DuckDuckGo Forums

  • After commenting the line with <!--<Param name="t" value="canonical"/>--> and restarting Firefox the t=canonical no longer shows up. Also thumbs up for the link to DDG forums.
    – Daniel
    Jan 24, 2015 at 20:18
  • 1
    After an update the files were back with their original content so I had to repeat these steps.
    – Daniel
    Mar 21, 2015 at 13:50
  • 3
    so it's the Canonical (Ubuntu parent) getting the revenue and not FF which initiated the search in the first place?
    – asgs
    Nov 23, 2017 at 6:56
  • Does not work on 20.04 LTS with Firefox 75+.
    – N0rbert
    Jun 15, 2020 at 19:10
  • @N0rbert see my edit on how to do it on 20.04.
    – Mitch
    Jun 16, 2020 at 4:02

Read the output from apt-cache show xul-ext-ubufox. Here's a partial quote:

Package: xul-ext-ubufox
Priority: optional
Section: web
Installed-Size: 378
Maintainer: Ubuntu Mozilla Team <[email protected]>
Architecture: all
Source: ubufox
Version: 2.8-0ubuntu1
Replaces: ubufox (<< 0.9~rc2-0ubuntu3)
Provides: firefox-ubufox, ubufox
Depends: aptdaemon, libglib2.0-0 (>= 2.26)
Recommends: firefox (>= 9.0)
Description-en: Ubuntu-specific configuration defaults and apt support for Firefox
 Adds Ubuntu-specific modifications to Firefox.
 Integrates the browser with Ubuntu to:
  * Enable searching for missing plugins from Ubuntu software catalog
  * Add the following options to the Help menu
    - Get help on-line
    - Help translating Firefox
    - Ubuntu Release Notes
  * Set homepage to Ubuntu Start Page
  * Display a restart notification after upgrading Firefox
  * Add ask.com to the search engines.
You can uninstall this if you prefer to use a pristine Firefox install.
Enhances: firefox
Homepage: https://launchpad.net/ubufox

Note the third-last line.

As for why, Canonical may earn some revenue but that's just speculation.

  • 1
    It is not actual for 20.04 LTS - here this package really contains nothing useful as XUL was removed.
    – N0rbert
    Jun 15, 2020 at 19:12

I am using Firefox 60.0.1 on Xubuntu 16.04.4 (64-bit). I had the same problem you face. The chosen answer provided by Mitch did not work for me. Instead, I resolved the issue by following this procedure:

  1. Open Firefox, navigate to Preferences -> Search, and remove the pre-installed DuckDuckGo search engine
  2. Download the search engine anew from the Firefox Add-ons directory; it can be found here
  3. Select this as the default search engine in the preferences

The string, &t=canonical, ceased to insert itself into my searches via the address bar thereafter.

I cannot tell you why the behaviour is there in the first place.


OK, this is how I did it successfully.

  1. Purged Firefox with

    sudo apt-get purge firefox

    and installed it from Mozilla's website in /opt/firefox.

  2. Created a symbollic link by

    sudo ln -s /opt/firefox/firefox /usr/bin/firefox
  3. Replaced the newly created something.release folder in ~/.mozilla/firefox with the one from my existing old profile making sure the name is exactly the same (rename the old release folder as the new one and then delete the latter).

  4. Created a new application shortcut.

All my previous user information and settings are preserved.


The above answers not working on a new versions of firefox. Because of that I recommend downloading firefox from official website and making a symlink

sudo ln -s /path_to_downloaded_firefox_executable_file /usr/bin/firefox

To remove "canonical" and other non-standard ubuntu things from firefox search string, delete contents of "/usr/lib/firefox/distribution/searchplugins/locale/" directory.

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