What does the Resource signal "changed" do?

SIsilicon28

I'm making another plugin, and it requires that I have two similar materials that need to keep most of their parameters the same. I looked through the docs and found the changed signal in the Resource documentation. I tried to use it, but whenever I change a value in the material, nothing happens. Is that what it's meant to be used for, or something else?

The docs: http://docs.godotengine.org/en/latest/classes/class_resource.html#class-resource

EzPizza

The signal probably doesn't detect changes to the resource but changes to the "resource_name" or "resource_path" variables. I assume that it's only when you replace the material entirely that the signal will be called.