DAV property name: urn:schemas-microsoft-com:exch-data:expected-content-class
The PidNameExchDataExpectedContentClass property is an array (list) of content class names that are designated as expected for items in the Folder object. This property does not itself define these content classes and does not define in what Folder object or Folder objects the associated content class and property definition items are kept. Applications SHOULD search for these definitions within the Folder object's schema scope. Additionally, the PidNameExchDataExpectedContentClass property SHOULD NOT impose a restriction on what the value of an item's content class can be; it simply designates the list of names as expected for items within the Folder object.
The PidNameExchDataExpectedContentClass, PidNameExchDataSchemaCollectionReference ([MS-OXPROPS] section 2.433), and PidNameExchDatabaseSchema ([MS-OXPROPS] section 2.431) properties SHOULD be used together to define a Folder object's schema. Folder objects can contain separate content class and property definitions specific to a particular application.