The Da Vinci HRex specification has an extensive decision tree and set of pages that describes the alternative exchange architectural approaches that FHIR provides and tries to provide guidance on how to choose among them. These were created to not be Da Vinci-specific with a hope that they could be migrated into the FHIR core specification as part of R5. This was, in fact, asked for by some HRex balloters as well.

I would like to move the pages here: build.fhir.org/ig/HL7/davinci-ehrx/exchanging.html into the core spec, likely under the link to FHIR Workflow under Adopting & Using FHIR on the FHIR documentation page.