A Main Entry is an Entry that can be used as a starting point for the data retrieval in a Model. Most Models use only one or two Main Entries. All other Entries are accessed as Subentries.
Model Developers can only use Main Entries or Entries that are accessible as Subentries. All other Entries that are defined in a DID Module can not be used by the Model Developer. Which Entries can be used as Main Entry is defined in the DID.