The user account that last wrote this version of the resource.
A display convenience, not an audit record. It exists so a version list can say who touched each
version without fetching a Provenance per row. Anything that needs to REASON about authorship --
rather than print it -- should read Provenance or the resource's own author element.
The value is an identity-provider subject, not a Reference. It names a user account; not every
writer has a Practitioner resource, and a dangling reference would be worse than a string a
consumer can match on. Resolving it to a person needs the identity directory, which this guide does
not describe.
Readers should expect two canonicals. This publishes under this guide's base; the EMR writes it
today under http://services.well.com/fhir/StructureDefinition/UpdatedBy, and because
this rides meta on every version of every resource ever saved, the old address persists in version
history even after writers move. Match both addresses exactly. The two share no segment, so a suffix
rule does not reach the pre-migration one and a reader built on it misses every pre-migration
version. The handbook's Canonical URLs page indexes every published artifact in this position.
May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.
Comments
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.
Source of the definition for the extension code - a logical name or a URL.
Comments
The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.