https://techcrunch.com/2018/11/15/mozilla-adds-website-breach-notifications-to-firefox/

Mozilla is adding a new security feature to its Firefox Quantum web browser that will alert users when they visit a website that has recently reported a data breach.

When a Firefox user lands on a website with a breach in its recent past they’ll see a pop up notification informing them of the barebones details of the breach and suggesting they check to see if their information was compromised.