Need understanding of NVDA HID usage page matching

[Poon-G]

Hi NVDA team,

I am trying to understand how do you match braille HID device usagepage: https://usb.org/sites/default/files/hut1_21.pdf with HIDP_CAPS caps.usagepage?

If forked this client sample: https://github.com/microsoft/Windows-driver-samples/tree/main/hid/hclient (which uses same hidpi and hidsdi api's that NVDA is using) and I read the value of caps.usagepage but I don't get the matching braille usage page as 0X41. I have Orbit20 device, and I know it's a hid device, but I get the caps.usagepage as 0XBB.
I don't see any other changes in hidBrailleStandard.py before getting usagepage but I see there is baum.py handling some HID stuff too which I don't understand. Why baum.py has HID checks and why is it needed specific for each device? Could you please explain this concept to me.

Thanks.

[Poon-G]

waiting for someone to help me in this regard.