The current text says:

refines
Identifies the expression or resource augmented by the element. The value of the attribute must be a relative IRI [RFC3987] > referencing the resource or element being described.

Is the relative IRI true? All the examples I have seen for refines is actually a fragment ID, with the ID referring to a meta element. We would have to find the exact formalism, but I do not think I can say refines="../otherpackage/#otherid", can I?