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

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

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.

• https://support.mozilla.org/en-US/kb/customizing-firefox-using-autoconfig
• https://support.mozilla.org/en-US/kb/customizing-firefox-using-policiesjson
• https://github.com/mozilla/policy-templates/

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

But i want it to be defaulted so when i build it it always has those settings without having to put these files

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.

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

• /questions/1421343 Firefox source code: How Do I set custom preferences or settings?