With the release of Firefox 67, the Mozilla Foundation will release Firefox Monitor as an additional extension by default. For those who do not know, today it is an autonomous service with which users can find out if their data has leaked.
This service will be publicly released to all Firefox users and will provide real-time alerts when a user visits a site that has been tampered with and has leaked data.
The feature though does not work on Firefox 65 and 66.
According to bug tracker (#1, #2), users who have already subscribed to the Firefox Monitor receive a notification of the pages that have been compromised. Also, if the site corrected the security gaps after the data breach and leakage, then the browser will not display any alerts.
Enable Firefox Monitor add-on in Firefox 65 and 66
Firefox Monitor is already available in Firefox 65 but is disabled by default. To work, you must turn it on manually. Let's see how:
Start your Firefox browser and in the address bar type: about: config
An internal page will open. Click the "I accept the risk" button to continue.
Then, in the search bar, copy and paste "extensions.fxmonitor.enabled" and the setting will appear.
You will find that his value is set to False. To change the value to True, double-click it. This will turn Firefox Monitor into your browser.
Restart your Firefox browser.
If you are now visiting a site that is already in the list of pages that have been violated by HaveIBeenPwned, a warning will appear in the URL bar to alert you that the page has broken and data has been leaked.
See her full list of the websites that the Mozilla Foundation uses.