It indicating best time for departure by a car. It use optymalization by using speed and direction of wind from a weather forecast

Just select the time on the bar, and the optymalizer show you a best time for your departure, basing on the weather forecast

To download the forecast for your location, the location is transmitted to https://open-meteo.com without any other identifying information.
According to the declaration https://open-meteo.com/pl/features#terms, this data is not saved.