This is the ValueSet that contains all the codes in US Core Problem or Health Concern (http://hl7.org/fhir/us/core/ValueSet/us-core-problem-or-health-concern) and US Core Problem or Health Concern (http://hl7.org/fhir/us/core/ValueSet/us-core-problem-or-health-concern). E.g. what you have to deal with if you get resources containing codes in either of them