Not much, really. Unless the device has been created to work with WebUSB, you first need to manually add a udev rule (on Linux) or replace the driver with WinUS

Not much, really. Unless the device has been created to work with WebUSB, you first need to manually add a udev rule (on Linux) or replace the driver with WinUSB (on Windows) before you can access it through a browser. Even then, the user needs to select the device from a list, like you would when giving a site access to your camera.