model diagram is slightly inconsistent with spec
Apologies if I'm not interpreting the model diagram in Section 2 correctly, but it looks to me that the annotations arrow on the right side is directed from "Anno." to "Anno. Page". This is inconsistent with the spec, which says that Annotation resources must not have the annotations property.
I also noticed an omission that seems fairly easy to add without changing the diagram much (Range may have start). I don't have a strong opinion on this, and I understand that diagramming all possible relationships would hurt readability, but I thought I'd flag it.
Yup, agreed! That arrow should just be deleted. And agree should be easy to add Range -- start -> Canvas
Diagram will need drastic rewriting for 4.0, but should take these changes into account at that point.