So called "Easter Eggs" — little hidden jokes — are a favorite guilty pleasure at Tesla, and following up on the newest one discovered we're going for a bit of a rainbow theme. Plug in to a charger, lock the car, and press the plug's button ten times, and watch the LED charging indicator lights cycle through a rainbow of color.
As with the Rainbow Road Autopilot, it's entirely possible the so-dubbed Rainbow Charge Port exists to test the various colors of LEDs that light up the connector port. On European Teslas, which use a larger plug that would obscure the US-style light ring, the taillight-embedded charging lights will also cycle through the spectrum of colors. Regardless of model, this only works with the car doors locked, which also locks the power connector. Pressing the power connector button on an unlocked Tesla will disengage the charger — you'll just get ten clicking sounds instead of getting to bask in the colors of the rainbow.
No word from Tesla on if this means the car is actually charging off rainbow power, however.