This is the most effective defense, as it prevents access even if an attacker has a valid password.

Use a trusted service like Have I Been Pwned to verify if your email address has been compromised in a breach.

A combo list is a massive text file containing pairs of usernames/emails and passwords, often formatted as email:password .

Files downloaded from hacking forums or unauthorized sites are frequently trojanized with malware (such as infostealers) that can compromise your own device.

The "Russia Combo List [Learnto com]" zip file appears to be a (usernames and passwords) derived from previous data breaches, specifically targeted at or originating from Russian domains.