The file is likely a 3D asset pack containing facial expression presets for the Genesis 8 (G8) figure in DAZ Studio. These assets are typically created by an artist known as Thunder-3D , who distributes content through various 3D marketplaces.

: Morph sliders found in the "Parameters" or "Posing" tab that allow you to adjust the intensity of the expression (e.g., a "Smile" dial set to 50%).

You can find artist profiles and official store pages for "Thunder-3D" on platforms like: