The is part of the PCI Express (PCIe) busPCIe Root Port refers to a connection point on the motherboard's chipset for PCI Express devices. The 1BBF - 1BBF identifier is a device ID that identifies the specific PCIe root port model and version.

In simple terms, this is an interface on the motherboard or chipset that allows for high-speed communication between the CPU and connected PCIe devices. If you're seeing this device in Device Manager on Windows, it's likely that the driver for this PCIe Root Port is missing or not properly installed.