Mozilla's has added a new feature to their desktop Quantum Browser that displays a warning from Firefox Monitor when visiting a site that previously had a data breach. These warnings are designed to alert people about possible concerns and to suggest they check their email to see if it was part of the breach.
Firefox Monitor is a free service that utilizes the data from Troy Hunt's Have I been Pwned site to alert users when their emails were included in a hacked site's data breach. Previously, to use this service, Firefox users had to go to the Firefox Monitor site and enter their email to check for breached accounts and sign up for notifications.
Now, all Firefox users will be shown alerts when they visit a site that has previously been breached. These alerts will provide a brief summary of the data breach and a button that will bring you to the Firefox Monitor service so that you can check if your email was affected.
When these alerts are displayed a user will have the choice to click on the Check Firefox Monitor button to go to the Firefox Monitor site, click the Dismiss button to close the alert, or click on the down arrow to select "never show Firefox Monitor alerts" so that these types of alerts are disabled.
According to Mozilla, these alerts are not designed to be intrusive and "will appear at most once per site and only for data breaches reported in the previous twelve months."
While Mozilla has stated that these alerts are now live, I have not been able to get one to display by visiting numerous sites that have been breached over the past few months. This could mean that the feature is slowly being rolled out to Firefox users and it may take some time before it become available for you.
If you do see one of these alerts, please let us know what site triggered it for you.