This is an example binding showing some expected values, but we anticipate that various jurisdictions will define when payload formats make sense, and include localized codes and valuesets in their implementation Guides. We have however included a specific FHIR based CodeSystem underneath to provide the "none" or "any" for general usage. It looks like IHE has provided a recommendation here too: https://build.fhir.org/ig/IHE/FormatCode/ValueSet-formatcode.html