This is a AC mount + Phone holder thats fits in the AC outlet to the right behind the steering wheel on a Tesla Model s (probably fits in the other outlets as well as on a Model X but haven't tried).
The phone dock is fitted for a Pixel 2 XL that has a Rhinoshield Crashguard bumper. And a USB-C (voxlink) cable.
The holes are for 2x 20mm M4 screws and bolts (to push the plates outwards).
Link to the Autodesk Fusion 360 file: https://a360.co/2w4HNHV (it also contains a photogrammetry model of the surrounding are of the car)
Used 100% infill for the plates and 60%-80% infill for the AC Mount and the Phone Dock