Comment:

This profile does not require query parameter "category", but this is the most helpful query parameter, as category is a rollup of many types that are in a single category.

Also, the new clinical-note seems to presume category (class) is included

type is a much less well managed valueset accross any domain, as it needs to represent actual document type. Where category is a more controlled valueset due to the ability to group many types into one category. (See IHE Metadata Handbook)

Summary:

Add support for Category in DocumentReference