The only one I've seen that works for the Model 3 is "Mars" which turns on the mars easter egg. From what I've read the main usage is what @Randy Spencer says, a way to enable diagnostic mode.If you hold the Tesla logo for a few seconds it asks for an access code.
What does the code access???
This is correct, only the front two ports have a data connection. I've never seen where Tesla recommends a size for the drive though. 265GB (or 256 ) is currently way overkill for the dash cam.This might be a no-brainer and I am lacking that brain partition, but I had to dig around to find out which USB ports would work for a USB drive to record dash cam info. Apparently, the two in the front console are the only ones that connect to the computer. (The rear seats ones are for charging only.) Unless you want to disconnect one of the phone chargers, you have to install a hub to increase the number of USB ports, and use a recommended 265 GB drive.
Please let me know if this is not correct. Dear hubby was looking for the 3rd front port until he realized the manual stated "Model 3" USB front ports, not "3 front ports"...