Knowing the source (like a specific gaming forum or a driver site) would help me give you a much more detailed breakdown.
If you have this file and want to see what is inside without risk:
: Before extracting, it is highly recommended to upload the file to VirusTotal to check for malicious content.
: "G3D" is a common file extension for 3D models or engine data. This could be a community-made collection of assets (like mods for a game like Gothic or Minecraft ) optimized for Radeon hardware.