Firefox lets you view and edit all user preferences in its about:config page. Till now we used to tweak /disable some Firefox features using about:config preferences, third-party add-ons can change Firefox preferences without user consent, Mozilla taking steps protect you from 3rd -party add-ons by disabling them by default from Firefox 8 release onwards, Preferences Monitor is a Firefox add-on monitors about:config preferences and notifies of any unwanted changes.

Preferences Monitor for Firefox

Here the genuine case where Firefox it self  makes the changes, or extensions also make changes to their own preferences or to private Firefox preferences. In all above three cases, you’ll be notified on the Error Console with “More Info” button.

When you/user him self makes changes to Firefox about:config Preferences you won’t be notified. When extensions make changes to Firefox preferences, Preferences Monitor notifies that with a Notification box, click on More info button to open the Error Console to find the exact line of code where the change was invoked.

For a novice user, this extension lets him know that when changes to Firefox about:config Preferences happened is that some extension changed its or Firefox preference where the basic info still might be helpful,  but lot of users don’t have knowledge of finding exact line of code where preference change taken place and for checking the add-on source code.