These files often originate from data breaches or phishing campaigns.

Turn on Multi-Factor Authentication (MFA/2FA) for your email and all linked accounts.

Attackers use "checkers" or "brute-force" tools to see which pairs still work.

In cybersecurity research, a "combo list" refers to a plaintext file containing sets of credentials.

Update your email password immediately to something unique and complex.

Check your "Logged in devices" or "Recent activity" for any unrecognized access. 📖 Understanding "Combo Lists"

They are frequently sold or shared on hacking forums for "credential stuffing" attacks.