In it, he shows an example of using all three ESP32 UARTs from an Arduino program. He calls the third port “secret” although that’s really a misnomer.

Raspberry Pi and Arduino get mentioned a lot in DIY projects, but they aren't interchangeable. It's important to know which one is better for different tasks.

The “N” in CAN stands for network, after all. The trick is to create a device ID for each desired CANSerial interface, which is done in his library using the usual Arduino setup step.