This is a bad idea, for multiple reasons.
https://www.troyhunt.com/here-are-all-the-reasons-i-dont-mak...
>Most breaches already contain hashed passwords
It could show the hash instead.
>No, it's not ok that these passwords are already out there
So it's better that people have to pay for it instead of getting this information for free?
>Because it's important to say "I don't store passwords in HIBP"
This is a personal choice.
>I'm not your personal lookup service
The idea is that this would be done by the site itself and would not require manual work by the owner.
I don't think he meant "show the actual data," I think he meant "what leaked? My name, address, phone number, email, medical records, payment history, bank account number?"
We get a "your private data is now public" email, but knowing exactly what data turns that from a depressing statement on how much corporations value their customers' privacy into something actionable.