It looks like you have a split archive file for the , which was a major content patch released in late 2022.
Players must manage Acute Radiation Syndrome (ARS) using gear like Hazmat suits and Lead Plates. SCUM.GOING.NUCLEAR.Early.Access.part01.rar
Includes Potassium Iodide pills to block radiation and Geiger counters to detect hotspots. You can read the full patch notes on SteamDB or the official Steam News Hub . It looks like you have a split archive