A mouse may be configured for 125 Hz, 500 Hz, 1000 Hz, or higher. But when you run a polling rate test in a browser, the displayed number does not come directly from the mouse firmware or raw USB packets. It represents the timing of mouse movement events that reached the webpage.
Source: [Dev.to](https://dev.to/umairaalam/what-browser-mouse-polling-rate-tests-actually-measure-4nei)