I can't directly answer your question. Obviously Apple knows the layout of all the keyboards it has shipped, so it could just be using the vid/pid of the keyboard. But if you can control the USB descriptor of your device, and it isn't actually a keyboard, why make it emulate a keyboard? If you want keyboard-like functionality, just make it a vendor-defined device. The OS won't grab it and the device won't send keystrokes when you don't want it to, but you can still access it using the HID Manager.

Either you expect the + operator on arrays to do something it does not do, or you don't appreciate what you're applying the + operator in the expression { $0 + $1 } to. From https://developer.apple.com/documentation/swift/array static func + (lhs: Array<Element>, rhs: Array<Element>) -> Array<Element> this is the + you are using - it takes an Array of ints on each side, and returns another array of ints. The new array is a combination of the two (by appending the $1 to $0), not an array constructed by member wise addition. To do what you intend, you need to dip one level deeper so that you call zip on an array of ints, not an array of arrays of int. Then the + operator would be the usual one which adds two integers.

2003332927 is 0x77686F3F or 'who?' (the macOS Calculator is your friend, use cmd-2 for the programmer's version). 'who?' is kCMIOHardwareUnknownPropertyError Sorry I can't help you further than that