This code system http://terminology.hl7.org/CodeSystem/push-type-available defines the following codes:

CodeDisplay
specific Specific requested changes
any Any changes
source As defined by source
 <status value="draft"/> <experimental value="false"/> <date value="2018-06-05T14:06:02+00:00"/> <publisher value="HL7 (FHIR Project)"/> <contact> <telecom> <system value="url"/> <value value="http://hl7.org/fhir"/> </telecom> <telecom> <system value="email"/> <value value="fhir@lists.hl7.org"/> </telecom> </contact> <contact> <telecom> <system value="url"/> <value value="http://hl7.org/fhir"/> </telecom> <telecom> <system value="email"/> <value value="fhir@lists.hl7.org"/> </telecom> </contact> <description value="Type of alerts/updates the primary source can send"/> <caseSensitive value="true"/> <valueSet value="http://terminology.hl7.org/ValueSet/verificationresult-push-type-available"/> <content value="complete"/> <concept> <code value="specific"/> <display value="Specific requested changes"/> </concept> <concept> <code value="any"/> <display value="Any changes"/> </concept> <concept> <code value="source"/> <display value="As defined by source"/> </concept> </CodeSystem>