Oculus decided to hide the fact that the Rift ‘sensor’ is a bog-standard webcam. Normally, when you plug a webcam into a USB port, the camera announces itself as a device in the USB video class (uvc), and the host PC then loads the standard uvc camera driver, and the camera works plug&play. The Rift camera is still a uvc camera, but in the USB descriptor that’s sent to the host when it’s plugged in, the byte that should say ‘video class’ says ‘vendor-specific class.’ That’s why it doesn’t show up as a camera when you plug it into a PC without Oculus’ driver software installed.