In addition it must provide the signatures for operations defined by the Object Request Broker (which transmits requests over the network) and the Basic Object Adaptor (which translates method requests to actual object method or function invocations).
Access to the ORB and BOA is usually provided by means of so-called pseudo-objects, objects described by interfaces in IDL which are not necessarily implemented as ordinary objects. As an example, the Object interface describes the functionality that each IDL-defined object has.