These lists are rarely from a single hack on Google itself. Instead, they are compiled from various unrelated data breaches where users have reused their Gmail address as a login for other websites. When those smaller sites are compromised, the credentials are added to a "combo list". 3. The Use Case: Credential Stuffing
any suspicious emails that use your old password to threaten you; these are typically mass-sent scams. GMAIL 1K UHQ.txt
: Specifies the quantity of entries (lines) in the file—1,000 pairs of usernames and passwords. These lists are rarely from a single hack on Google itself