Knowing the context (like an alert or a file you found) can help me give you more specific advice.
The "135k" indicates that this specific list contains approximately What is a Combo List?
Hackers use these files for Credential Stuffing . They use automated tools to "stuff" these 135,000 combinations into the login pages of other popular sites (like Netflix, Spotify, or banking portals) to see if people reused the same password [1, 2].