What are these screw heads called? What tool is used?

Nah, they were an option on flip=top gas cap cars. Tri-groove screws. I bought a driver a while ago. Here's an example, I'll bet there's better suppliers.

https://www.amazon.com/dp/B072HPML7G/?tag=fabo03-20

Here's one from Dante's:

Challenger Charger Barracuda GTX Flip Top Fuel Cap Theft Proof Screw + Tool | eBay
Factory option? I did not know that.
Thank you!