See revised text in context:  [https://build.fhir.org/ig/HL7/davinci-pdex-plan-net/index.html The text has been significantly expanded to address this issue.| https://build.fhir.org/ig/HL7/davinci-pdex-plan-net/index.html ] Revised test: As shown in the diagram below, it describes the architectural considerations for attesting to, validating, and exchanging data from a central source of validated provider data as part of a Validated Healthcare Directory or VHDir, as well as a RESTful FHIR API for accessing data from a VHDir. The VHDir authors developed the IG to support a conceptual, centralized, national source of healthcare data that would be used across multiple use cases.