Malicious software can infect a personal computer and "scrape" saved passwords directly from browsers, later compiling them into text files for sale on the dark web. The Dangers of Searching for or Downloading These Lists

These files are typically the result of or infostealer malware attacks.

Seeking out these lists is highly risky for several reasons:

When a website or service is hacked, attackers may steal a database of usernames and passwords. If users reuse their Gmail password on that site, those credentials end up in a ".txt" list.