[andrewmunsell]

It's actually both, at least in the US.

Tesla has the "Magic Dock", which is the built-in CCS adapter that unlocks when you use the app with a non-Tesla car. This is rolling out in a few places.

The other thing is that "NACS" (North American Charging Standard, the same physical plug that Teslas use but with the CCS protocol, with some minor backwards compatible changes for optional higher voltages) is being adopted by almost every EV brand, beginning ~2025. Further, these same brands have committed to providing or selling NACS-CCS adapters to existing cars so they can use Tesla chargers, even without buying a new model of car.