Proposed Wording: The DocumentReference and Media resources allow conveying binary content (via attachment) or pointing to one (as a Binary or non-FHIR URI) along with the metadata around that resource, and as such are searchable. Binary resources do not support 'search'.

While CDA and PDF documents are conveyed as Binary (because they cannot be expressed natively in FHIR), [FHIR Documents] do not need to be similarly encoded and can be sent natively in FHIR using [Bundle]. However, in some situations FHIR Documents may be sent as a Binary if there is a need to treat them the same as other types of documents or binary files.

Comment:

We need to provide guidance about how Media and DocumentReference relate to Binary and when to use each. We also need to discuss passing FHIR Documents as Binaries - both that unlike CDA we don't need to, but that in some cases we might want to.

Summary:

Boundaries & Relationships needs Media, DocumentReference and Document