YOUR
HISTORY

A screen-based test can't tell you much on its own — your display, your lighting and your distance all move the number. What it can do is compare you against yourself on the same screen. That needs a record, and a record needs somewhere to live.

This one lives on your device, in your browser's own storage. It is off until you switch it on, nothing is written before that, and switching it off erases what was kept. There is no upload — the code that stores it has no way to send anything anywhere.