I wanted an ESP32 camera board to act like an ordinary webcam. Not a Wi-Fi
stream, not an access point, not a little HTTP camera server: a real USB Video
Class device that Linux would expose as /dev/video0.
The working hardware was a Seeed XIAO ESP32S3 Sense. That matters because the board has native USB, PSRAM, and a camera module. A generic ESP32-CAM module without native USB cannot become a normal USB webcam just by changing Python or host-side code.