This is the ValueSet that contains all the codes in Allergy reaction substance value set (https://terminology.dhp.uz/fhir/core/ValueSet/allergy-reaction-substance-vs) and Allergy reaction substance value set (https://terminology.dhp.uz/fhir/core/ValueSet/allergy-reaction-substance-vs). E.g. what you have to deal with if you get resources containing codes in either of them