If you're a Google user, you would know the tech giant offers a password manager that syncs across Chrome and your Android devices. Now, the service adds a "password checkup" feature that analyzes your logins to make sure these aren't part of a massive security breach. This feature was previously available as an extension, but now it's being added right into your account controls, and you'll see it at the forefront of passwords.google.com. It's similar to what site haveibeenpwned.com is doing.
Your login credentials will be compared to the millions of known comprised accounts to see if your account has been part of any significant breach. According to Google, it monitors the dark web to some extent for collections of passwords. But for the most part, it makes password comparisons by crawling through the open web. And if it finds that any of your passwords are part of a breach, Google will encourage you to change this password. It'll also let you know if you're using weak passwords. The company promises that the passwords are hashed and encrypted before it's sent to Google, and that "it has no way of seeing your data." Also, that "any warning that's generated about your details is entirely local to your machine."
Source: The Verge