This is a mounting plinth for a gearbox tunnel courtesy light, a modern version of the original equipment on early models. It uses a small LED light bar as shown in the photos, and it's plenty bright to illuminate the dashboard from between the seats. I found a 2 pack of them at a local Menard's store. The switch is a basic on/off rocker i found locally.
This should be printed upside down with support for the light bar area. My print has a noticeable layer shift toward the top, but it's not apparent once installed so i didn't print a cleaner version. Mine is mounted with a strip of the hook side of hook & loop tape, and that sticks to the carpet.
This was drawn with OnShape, if you have an account you can customize the drawing for yourself here: