| PDAttributeObject | An attribute object. | code | html |
| PDStructureNode | A node in the structure tree. | code | html |
| PDDefaultAttributeObject | A default attribute object. | code | html |
| PDMarkInfo | The MarkInfo provides additional information relevant to specialized uses of structured documents. | code | html |
| PDMarkedContentReference | A marked-content reference. | code | html |
| PDObjectReference | An object reference. | code | html |
| PDStructureElement | A structure element. | code | html |
| PDStructureTreeRoot | A root of a structure tree. | code | html |
| PDUserAttributeObject | A User attribute object. | code | html |
| PDUserProperty | A user property. | code | html |
| Revisions | code | html |