XForms 2.0 custom attributes

Question

Can we add foreign attributes into the XForms 2.0 documents inside the elements that have the Common attribute?

I'm trying to add a custom attribute inside the model element but not sure if im allowed to.

Answer 1

My understanding is that you can always add foreign attributes and that it is not the intent of XForms to prevent that.

UPDATE: To clarify, I mean attributes in a namespace different from XForms.