Hello Ivo,
I can only agree with the previous users. We use Windy almost daily for weather analysis and plan world championships and world records with the plugins for trajectories and soundings. It would be really fatal if these excellent functions were to disappear. Then we would only have the option of returning to NOAA and Meteoblue. With the plugin, Windy offers a very uncomplicated way to create trajectories with different models. The plugins are almost self-explanatory, even for less experienced users and newcomers.
So I hope that the plugins will either continue to work like this or be integrated by you into windy itself.
Besides, windy would not be the only site with 3rd party code in the browser. Every plugin that the user installs in the browser can be integrated into the site. Perhaps a corresponding disclaimer would be a possibility? Or real browser plugins that the user has to actively install? In any case, the api should be maintained accordingly.
Windy has found many supporters in the balloon community in recent years. It would be a real shame if this function were to be removed.