another question: the prpc examples use "Van Ooijen Technische Informatica
CDC-ACM class devices (modems)" for their USB VID/PID: https://the-sz.com/products/usbid/index.php?v=0x16C0&p=0x27DD&n=
(no clue who that vendor is, but CDC-ACM sounds like the wrong class for prpc? though of course this is just the PID and not the actual class, but it might confuse OSes into loading a wrong driver in the worst case?)

now i'm wondering: is there a good VID & PID which can be used for purely internal devices (for a company not owning a VID and not planning on selling any USB devices => no need to get a VID assigned)? i've found the VID "generic": https://the-sz.com/products/usbid/index.php?v=0x1209
so i'm now thinking to just use VID 0x1209, PID 0x0001 (Generic - pid.codes Test PID)