<!ENTITY legal-notice SYSTEM "legal-notice.xml">
Entities can be declared in a DTD file that is external to the edited document (the external DTD subset), or declared in the edited document (the internal DTD subset). The declarations of internal and external entities in the internal DTD subset can be changed and removed.
Change the declaration of an entity
Change the declaration of an internal entity
You can change the name of a declared internal entity (but not its content).
Change the declaration of an external entity
You can change the name of a declared external entity and/or the name of the file (but not its content).
Remove the declaration of an entity
Remove the declaration of an internal entity
You can remove the declaration of an internal entity if there are no references to this entity.
Remove the declaration of an external entity
You can remove the declaration of an external entity if there are no references to this entity in the document.