This OID returns the three-byte PCI class code register for this function, encoding the programming interface, sub-class code, and base class code as defined by the PCI Local Bus Specification. An admin or management tool decodes these bytes to automatically identify the general category of device, such as mass storage controller or network controller, without relying on a free-text description. For example, a base class byte indicating mass storage combined with a sub-class byte for SCSI would confirm this function is a SCSI storage controller.