In the USB specification, the bDeviceClass field of a device descriptor tells the host computer what type of device it is dealing with. When this value is (Class 00), it signals that the device is not limited to a single predefined class at the top level.
If you meant a (e.g., feature descriptor, HID report, kernel driver dispatch), let me know and I’ll give a more specific example. usb\class_00&subclass_00
The USB subclass codes are used to further specify the device subclass. In the USB specification, the bDeviceClass field of
Devices with a class code of 00 and a subclass code of 00 are often referred to as "vendor-specific" devices, as they require custom handling by the host computer. The USB subclass codes are used to further
SP_DEVINFO_DATA devInfoData; // iterate and check compatible IDs for "USB\CLASS_00&SUBCLASS_00"
The USB class codes are defined as follows: