That’s what they’re saying - you can use an ESP32 device as a serial proxy without having to do anything special. If you already have a device attached to it you could use the socket:/… syntax below.
Per the integration documentation:
The serial port the TV is connected to. This can be a local device path or a remote serial proxy URL. For example, /dev/ttyUSB0 (USB adapter), socket://192.168.1.100:2000(network proxy), or socket://esphome-device.local:6638 (ESPHome).