When you download a PS3 game in "folder format" (often referred to as a JB or Jailbreak folder), you will typically see two main components alongside the actual game data: Help:Validating PlayStation 3 game dumps - RPCS3 Wiki
If the tool detects a missing SFB file in your JB folder, it often offers to generate a generic one based on the game's PARAM.SFO file. Method 2: Regenerating via IRD Files