I have a group layer in geoserver with all layers having one style each.
However, for the legend I want to refer to an "external" SLD (basically a simplified "dummy legend"). The SLD is in the same workspace as the group layer and I guess you can specify the SLD you want to get by GetLegendGraphic Parameters? Here specifically, I'm thinking of the SLD parameter.
The solution (I think) is something like this:
In the SLD documentation it says thatt you can refer to an external SLD by a URL. How do i know what URL to use as a parameter?