That site goes through many leaks that happened before and checks if your email has been leaked https://haveibeenpwned.com/
one of my emails got leaked several times (good thing I don’t use it for important stuff)
This, however, is VERY IMPORTANT and requires you to change passwords on a few accounts fast. Someone managed to get into my account once with this (Crossout account lmfao)
My school email got breached in the mangadex breach, but it can’t even be spammed with emails cause it can only recieve emails from my school district or things I subscribed to lol