XMI12 — Section 6.12 needs rewriting.

Section 6.12 deals with the mapping of meta-model DataTypes to XMI.
A key requirement of XMI was that XMI producer and consumer software
could generated from a meta-model, or written to be "table driven" using
the meta-model as input. Such software has to be compatible with any
hand-built XMI software built according to the spec. The problem with
Section 6.12 (as written) is that it seems to break this requirement.
(See point 4 below).

By saying "This general solution ...", section 6.12 seems to try to
define a mechanism for tailoring XMI data type mappings. Unfortunately,
it is woefully inadequate as a specification. It is unimplementable as
written.