: Many "direct download" links for these files are actually wrappers for infostealers or ransomware .
If you are concerned that your data might be included in a leak like this, the best practice is to check authorized breach notification services like Have I Been Pwned .
: Brief mentions on threat intelligence sites or forums like RaidForums (now defunct) or BreachForums where "combo lists" are traded.
There is no reputable or "useful" blog post for because it refers to a specific combo list or credential leak file typically found on hacking forums and "leaks" repositories . These files generally contain lists of usernames and passwords (often formatted as email:password ) sourced from various data breaches.
To help you find what you need safely, are you looking for on how these leaks happen, or are you trying to verify if your own data was compromised in a specific event?
Searching for and downloading .txt combo lists like "5Qatar" is highly risky: