It appears to be a Teensy 3.2

The "carrier" that everything rides on within the housing is clearly FDM printed as well. I assume these cameras (rated to 6,000 meters) are rather low volume products.

It honestly makes sense. You are paying for the pressure engineering, and can take advantage of an off the shelf camera system. Maybe use a special lens or filter or something but why bother customizing the software/hardware of the camera much.

They probably should still know what it's doing though...