Where the profile is derived from C-CDA on FHIR US Realm Header, the link in "This structure is derived from C-CDA on FHIR US Realm Header" on the StructureDefinition-<id>-html page is broken. This is a publishing issue and is due to what is most probably an issue in the publishing tool code. But to fix it until the code is fixed need to add the following to ccda.json for the base mapping for the US Realm Header profile '"base": "StructureDefinition-ccda-us-realm-header-composition.html"'.