XMI12 — XMI MOF Subset" optional compliance point.

This compliance point (11.3.1) is worrying. It means that a compliant
XMI implementation may be capable of transmitting/receiving metadata
described by a legal and meaningful MOF meta-model. For example, the
MOF Model itself has a number of References where the Reference's name
and the corresponding AssociationEnd have different names. Thus, XMI
support for the MOF Model is optional. This is in violation of the
XMI RFP requirements, and contradicts the intention of other parts of
the spec.

I suggest that the MOF and XMI RTFs jointly review the listed "optional"
MOF features in 11.3.1 with a view to either making them mandatory in
XMI, or removing them from the MOF Model in MOF 1.4.