The module entities file declares entities that are used within document type shell DTDs to integrate the module into the shell.
The module entities file is named "modulenameModule.ent".
There are two types of entities: type-specific parameter entities that integrate the module's element types into the appropriate content models (phrase, keyword, dl, etc.) and a domain usage declaration text entity that goes in the topic's or map's domain use declaration attribute to indicate what domains are being used in a given topic or map.
For the XML domain we only have element types specialized from <keyword>, so we only need to declare one type-specific parameter entity. The parameter entity is named "modulename-d-basetype", so in this case, the entity will be named "xml-d-keyword".