The base URL for the server to which questionnaire response associated with this questionnaire should be submitted.

Indicates that the form has been designed with an expectation that it will be submitted to the specified URI. If multiple endpoints are specified, expectation is that answers are submitted to all endpoints.

If no end-point is specified, then the form is not exclusively designed to be submitted to a specific site. If and where the form needs to be submitted or how the form should be internally processed must be inferred from external context or system business rules.

unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. In order 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 is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

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.

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.

Value of extension - may be a resource or one of a constrained set of the data types (see Extensibility in the spec for list).