[SOLVED] How to figure out the available options of xml tags?

Where can I find available attributes of several xml tags?
As an example: I have a visual node, defined as an OglModel loading a .stl file and with attribute color=”green”. Now I would like to make the model semi-transparent. I suppose that the possible attributes of OglModel can be found somewhere in the documentation, but it is not entirely clear to me yet. I fond the OglModel Class Reference at https://www.sofa-framework.org/api/SofaOpenglVisual/classsofa_1_1component_1_1visualmodel_1_1_ogl_model.html but it does not contain the “color” keyword. Its parent class does have a VisualModelImpl::setColor method, one with string input and one with four floats (r,g,b,a) and I suppose that the xml options get passed through that function somehow. While writing this post, I figure out the syntax by studying the cpp file itself and now I see that color=”1.0 0.0 1.0 0.5″ gives transparent purple (yay!). So this works by studying the code, but I still don’t have an overview of all available attributes.