Understand why some code systems don't display or resolve in the FHIR Specification.

Some code systems in the FHIR Specification, such as language tags, don’t display. Why is this the case?

There are a number of instances in the FHIR specification where CodeSystems are not displayed in the spec. This falls into two main reasons:

1.	The code system is too large for the publication tooling to handle. I think the full language code system falls into this category
2.	The  code system us Intellectual Property of another organization. This prevents HL7 from publishing a specification that incorporates the IP of another body. There is a note about this in the CARIN Blue Button IG: http://hl7.org/fhir/us/carin-bb/STU1/Terminology_Licensure.html

Onyx is evaluating how licensed code systems are incorporated into OnyxOs. Some of that may depend on how a client is implementing OnyxOs. It can quickly become a complex issue.