This code system http://hl7.org/fhir/v3/ResponseLevel defines the following codes:

CodeDisplayDefinition
CcompletionRespond with exceptions and a notification of completion
DdetailRespond with exceptions, completion, modifications and include more detail information (if applicable)
EexceptionRespond with exceptions only
FconfirmationRespond with exceptions, completion, and modification with detail (as above), and send positive confirmations even if no modifications are being made.
Nmessage-controlRespond only with message level acknowledgements, i.e., only notify acceptance or rejection of the message, do not include any application-level detail
RmodificationRespond with exceptions, completions and modifications or revisions done before completion
XnoneDo not send any kind of response