[GiuseppaAcciaio]

Do a bit more research: you'll find that Troy (the guy who runs the service) has been working on this for several years before any involvement with 1password, and so far he's been very transparent about what he does with breach data and also about his relationship with 1password. Whenever he gets access to an unverified dump he first tries to verify its authenticity with the company or service that was pwned, then gets in touch with people whose details are in the dump to verify if the data is real.

[a_imho]

I'm aware, but my question is how can I verify it myself instead of taking his word for it.

[edoo]

You'd have to download each of the public hack dumps and check for your email in them.