Mozilla Firefox gets open to display modified preferences only on about:config

[harlan4096]

Mozilla Firefox users will soon be able to display only modified preferences on the browser's advanced configuration page about:config.

All desktop versions of Firefox as well as Firefox Nightly for Android come with options to modify preferences using the browser's advanced configuration page about:config. Firefox Stable and Beta for Android don't support it. Mozilla launched a redesign of the about:config page in Firefox 71.

All it takes is to load the address in the browser's address bar to get started. The list is a treasure trove for advanced users who like to modify browser settings that cannot be changed using the built-in settings.

The about:config feature sets Firefox apart from other browsers who don't provide the same level of customization options.

Up until now, it was difficult to list only modified preferences. Preferences may be modified by the user but also by Mozilla, e.g. as part of an experiment or test. Modified preferences are displayed in bold on the page, and while it is certainly possible to scroll through the entire listing to check all modified preferences, it is time consuming and not the best approach because of that.

One option that Firefox users have is to open aboutupport in the browser to get a list of modified preferences; problem is, that list is not complete.

In April 2020, we published a quick hack to display all modified preferences on about:config. The trick still works, and it requires that you run code in the Web Console of the browser's Developer Tools while the about:config tab is the active tab in the browser.

Mozilla landed a change in the most recent Firefox Nightly build that makes things a lot easier. Engineers added a "show only modified preferences" checkbox on the page.

Just check the box to display all modified preferences on about:config. Firefox lists all modified preferences on the page and you can go through the list easily then. One caveat is that all modified preferences are displayed, and not only user modified preferences. hance is high that most preferences listed have not been modified by the user.

Closing Words

The option to display all modified preferences directly on about:config, without having to use the little hack to display them, is a welcome addition. The feature will land in Firefox Stable eventually so that all users of the browser may make use of it.

Now You: If you use Firefox, do you edit about:config preferences?
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