XMI24 — 5.2 rule 1c

5.2 rule 1c states "1c. If the schema has a target namespace, the targetNamespace attribute is present." This rule does not make sense as a rule for generating a schema! The rule must say what determines whether a targetNamespace is generated and what its value is (e.g. based on a property of the metamodel or a Tag).
Likewise rule 1d.

The issue is correct.

It makes sense to use imports for needed declarations from other metamodels which will be in other namespaces through the nature of XMI: hence the syntax should refer to Imports only rather than ‘ImportsAndIncludes’