A "repack" version of this DLL is a modified file designed to emulate these Steam functions, allowing a game to run without an active Steam license. Risks of Downloading Repack DLLs
Modified DLLs can be used to deliver malware, trojans, or cryptocurrency miners.
The original or steam_api64.dll is a legitimate component of the Steam Client API. It allows games to communicate with Steam servers for features like: Digital Rights Management (DRM): Verifying game ownership.
Accessing achievements, stats, and friend lists. Matchmaking: Connecting players to online servers.