I wonder how hard it is to make a fake USB printer.
Like, a printer that takes any printout and goes "yep, that printed just fine" but nothing ever comes out anywhere
@foone Linux is happy to be a USB printer for you: https://www.kernel.org/doc/Documentation/usb/gadget_printer.rst (I've done the gadget side of the USB mass storage class and it was basically fun and easy. I'm guessing the gadget side of the printer class is similar but who knows.)