The default value of an entity attribute has not been defined. If there is a default general entity, its value will be used as that of the named entity. If there is no default general entity, any attempt to use this default value will result in an error.
#0243 Markup Warning
ISO 8879, 7.9.4.3
The default value of an entity attribute has not been defined. If there is a default general entity, its value will be used as that of the named entity. If there is no default general entity, any attempt to use this default value will result in an error.