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How to change settings or preferences in firefox source code?

  • 6 replies
  • 1 has this problem
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  • Last reply by cor-el

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I want to change some settings in Firefox from the source code, and I cant figure It out. I Have Heard Of autoconfig but that's for in the directory of Firefox.

I want to change some settings in Firefox from the source code, and I cant figure It out. I Have Heard Of autoconfig but that's for in the directory of Firefox.

All Replies (6)

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Hi

If you are looking to work with the code of Firefox, this site will help you to get started:

https://firefox-source-docs.mozilla.org/index.html

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I have done all of those already, But I want the change the default preferences in firefox.

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There is no need to edit the source code to change the default value of a pref. You can do this via a policies.json file or via autoconfig.cfg file in case the pref is not supported by a policy.


To use Autoconfig, place two files into the Firefox installation directory.

  • on Windows, they go into the same directory where Firefox is installed
  • on macOS, they go into the Contents/Resources directory of the Firefox.app

The autoconfig.js file that specifies to use autoconfig.cfg is placed into the "defaults\pref" directory where the channel-prefs.js file is located. The autoconfig.cfg file is placed at the top level of the Firefox directory.

  • autoconfig.cfg and autoconfig.js need to start with a comment line (//)
  • autoconfig.js needs to use Unix line endings (LF instead of CR/LF)

The content of autoconfig.js:

//
pref("general.config.filename", "autoconfig.cfg");
pref("general.config.obscure_value", 0);
pref("general.config.sandbox_enabled", false);

These functions can be used in autoconfig.cfg:

defaultPref();	// set new default value, requires special data: format for localized prefs
pref();	// set pref, allow changes in current session
lockPref();	// lock pref, disallow changes
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But i want it to be defaulted so when i build it it always has those settings without having to put these files

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I have built firefox using mozillabuild but I want the change the default settings or preferences, for example the homepage or more preferences page. I want to do this directly from the code.

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I will lock this thread since you decided to create a new thread.