[azernik]

From the post:

"Because we are focused on building a Driver and not a vehicle, we’ve designed a versatile, integrated autonomous driving system that can be adapted to various platforms and use cases over time. Our versatile hardware approach allows us to reconfigure our sensors and generalize our AI to meet each platform's unique needs—whether it is the Ojai or the Hyundai IONIQ 5—providing the Waymo Driver an optimal view of its surroundings while streamlining for efficiency."

ie this is a sensor+software package for any vehicle that they install on.

My understanding of the text is that, to get this to run on the existing fleet, they'd need to go into the shop for sensor/computer replacement, but the text isn't explicit about that.