USB 2.0 BILLBOARD - what is this?

USB-C can support various different connections, but an individual USB-C connection probably won’t support everything that can be connected. That particular billboard component is part of the internal USB-C xHCI hardware, and deals with alternate mode operations. That component provides data that can be displayed to the user when some incompatible USB-C device is connected.

Could be Bluetooth or Wi-Fi module.

here is my similar readout from an older Mac Pro 5,1:

USB Bus:

Host Controller Driver: AppleUSBUHCIPCI

PCI Device ID: 0x3a39

PCI Revision ID: 0x0000

PCI Vendor ID: 0x8086

BRCM2046 Hub:

Product ID: 0x4500

Vendor ID: 0x0a5c (Broadcom Corp.)

Version: 1.00

Manufacturer: Apple Inc.

Location ID: 0x5a100000

Bluetooth USB Host Controller:

Product ID: 0x8215

Vendor ID: 0x05ac (Apple Inc.)

Version: 2.08

Serial Number: 002500C1B92B

Manufacturer: Apple Inc.

Location ID: 0x5a110000

TL;DR: Billboard is a hunk of the USB-C specs.