: These are often harvested from "leaks" or "dumps" on dark web forums or Telegram channels.

: 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.

: Validated accounts (called "hits") are then resold on marketplaces for a profit. How to Protect Yourself

: Generate unique, complex passwords for every single service so that one leak doesn't compromise your entire digital life.

A "mixed" combo list specifically implies that the credentials inside are not targeted at one specific site. Instead, they are a General Aggregation of logins from different sources across the web.