Yeah it was through android/Google that it popped up. On the password manager thing.I've not had it on TL but other sites. Generally when I have historically used the same password for multiple sites and its stored been stored in the browsers vault.
You can use sites like https://haveibeenpwned.com/ to check for breaches and info. iPhones also have something built into the Password keychain that shows compromised passwords and I am sure android will have something similar.