Title. 

It's just a lot of IGs! How many IGs are there now? Every country, sometimes province, and domain has their own profile stack. Just think of Da Vinci - US Core - Hrex - Pdex - CRD. Four IGs just to claim conformance to CRD. Now multiply that by a dozen domain areas, and then by a dozen countries. 

Typical argument – claiming a server supports an IG is merely a statement, not an actual capability. Importantly, not claiming support doesn't mean that the FHIR server doesn't support an IG. Also, documenting individual capabilities is much more useful to a client, than requiring that client to know the capabilities required by 10-100s of IGs. 

Instead the server should document it's capabilities, which match to the capabilities required by the IG. Things like: resources, searchparameters, security profiles, etc. 

I can accept that this IG is US Core. If every country gets to force explicit documentation of compliance of one IG – this is the US's. That seems fair (but it's probably not how it'll work out).

I think that this requirement got added in US Core 6. I think that I just missed hearing the rationale. What's the rationale?