Iray Advanced Render Settings?

Hi,
I just noticed an icon called "Iray Advanced Render Settings" under Render Presets > Iray. Anyone have info on what this icon does? It seems to do something "under the hood" but I haven't seen any changes when used.
I suspect that it is a left over helper script from the begining of the Iray era, but I have no proof of that.
Thanks!
Comments
It adds some new proeprties to the selected nodes - the iray matte, which allows the object to act as a shadow-catcher (showing shadows that fall on it but not itself rendering as a surface) and a tagging system that could be picked up by the renderer for example
Ah, thanks. Now I see why I didn't see a change. I was looking for deltas in the Render Settings, not in the Shader or Item Properties.