This is the ValueSet that contains all the codes in DDCC Composition Category Codes (http://smart.who.int/ddcc/ValueSet/DDCCCompositionCategoryValueSet) and DDCC Composition Category Codes (http://smart.who.int/ddcc/ValueSet/DDCCCompositionCategoryValueSet). E.g. what you have to deal with if you get resources containing codes in either of them