Refers to another code defined within the code system that is also subsumed by this code. I.e. This concept subsumes the referenced concept. Because meaning is inferred from hierarchy as well as definition, the presence of this extension modifies the meaning of the extended concept.
Project FHIR API
This is the location where you can find your resource using a FHIR client.
Simplifier FHIR API
The global endpoint is where users can search for all resources in Simplifier. Resources have a globally unique guid Id here.