Addition of Fronts
It wouold be incredibly useful to add the layer of "fronts" into the layers palet.
Fronts are not drawn by numerical weather forecast models, but by skill weather forecast meteorologists.
As Windy shows maps directly and automatically issued from weather forecast models, there is no way to show fronts.
Personnaly, I use to look at Temperature layer at 850hPa which gives a rough idea of the location of the different fronts...
To add to @idefix37 fronts are sometimes unmistakeable phenomena, but sometimes a bit vague and sometimes very vague. There may be a single front or there may be several lesser fronts succession, or just a weather change over a period of an hour or two to cooler temperature and a different wind vector.
There'a judgement and even a psychological component to what constitutes a front. A human forecaster will take the human impact into account in choosing whether to draw a front, how far it extends horizontally and when it has degraded sufficiently to drop it. It's a tough job for a NWP model - more of a neural problem - but expect it one day.
It's probably better to look at rain, temperature and wind change then decide if that's what you call a front.