Most places where the extensions weren't defined were either because there was a 'core' element on the Request resource or because the concept didn't make sense for the concept (e.g. "doNotPerform" on an Appointment).  However, we did find some where we believe the scope of the extension should be extended to include other resources.  Specifically: DeviceRequest - add doNotPerform, performerOrder Task - add doNotPerform, replaces, add performerOrder (also change to CodeableReference) SupplyRequest - add replaces, performerOrder   Appointment - add insurance, replaces   CarePlan - add insurance, relevantHistory?, performerOrder CommunicationRequest - add insurance?   Will create change requests for the relevant work groups to consider adding these concepts - either as core or by extending the scope of the existing extensions to include their resources.