I had similar with a website called Apollo. Story linked below[1].
Edit: Their opt out page and main site[2]. Notably, Firefox Developer Edition warned me and linked me to the main Firefox Monitor page, so it's something that's being built into Firefox.
Interesting, thanks for linking the story. I also had the same experience with Apollo.
Its frustrating since I never signed up for their services, and I have no control over who my data is sold to... Its getting to the point where I just assume all my data is pwned, and change passwords frequently
Edit: Their opt out page and main site[2]. Notably, Firefox Developer Edition warned me and linked me to the main Firefox Monitor page, so it's something that's being built into Firefox.
[1] https://www.wired.com/story/apollo-breach-linkedin-salesforc...
[2] https://www.apollo.io/privacy-policy/