@b-rochut I do not know if it is normal or not. Our example works well, as do other websites using our API. I would think you do something wrong. Session is counted only when map is loaded, working with already loaded map is not counted into the session limit. There is only daily limit. Free API works the same way as Professional API, only amount of features is different.
I would like to know the same. We want to use the API for an application that also contains multiple other Leaflet maps, where we don't want to show weather overlays, but since Windy replaces leaflet CSS it breaks the other maps that are not being created by the Windy API.
Android does not send the package name with requests. Or, to be more precise, it sends, but it depends on a version. So you need to add a domain it runs on. But read carefully Terms & Conditions, Windy API is allowed for mobile app only under certain conditions.