: Hackers use automated tools to perform Credential Stuffing . Since many people reuse the same password for their email, Netflix, banking, and gaming accounts, a single entry in a "Mixed-Combo" list can potentially unlock dozens of different services.

Because these lists are "mixed," they are unpredictable. A user might have their credentials leaked from a small, forgotten forum ten years ago, but if that password matches their current primary email, they are at high risk.

: Files with names like "Mixed-Combo.txt" are frequently bundled with Malware Samples or "Zips" found in sandboxed analysis environments. They serve as the "input" data for account-cracking software. The Risks of Credential Stuffing