Saves
The game saves in your browser, on your device. Nothing is sent anywhere. Clearing your browser's site data deletes the save.
A garage save holds your credits, driving time, owned parts, rig builds, the selected rig, finds you've collected, shop stock, stand color, bench light level, map unlock and saved courses. A rig build keeps its base rig, name, installed parts, wheels and paint.
You can export a garage save to a file and import it again, which is how to move it to another browser.