A "Publication" entity is a group of published entities in a CAD model (e.g. Body, Feature, Geometric entity, Parameter) to make them accessible for different users.
You need a specific license to get them. It's represented using the Dtk_MetaDataPtr class with inNode->GetNodeSubType() == DTK_TYPE_PUBLICATION.
You can retrieve the Name of the "Publication", and the published entity, defined by the Dtk_NodeConnector class.

The Dtk_NodeConnector class is used to specify a link to many types of data in a component,
for example to a Dtk_Node, a Meta data or a Geometrical Entity.