It is not any longer, the last update on github was made 3 years ago. Now Cameron works is not publishing new features on github.
Which features does the website have that are not in the repo?
eg WebGL support which was added last year in November
They are not, the only common thing is that they are Czech companies. Windytv provides ECMWF model (for free), which beats Ventusky in big way.
Can you explain the significance of that
ECMWF has been producing the best global forecasts in the world for many years. This will end in few years, but at the moment IFS, the model used at ECMWF, is the best in the world.
This is true, it routinely exhibits higher forecast skill than any of the US models.