Represents the "Subtype" entry of the cuepoint dictionary object.

It is an optional entry defined as part of the PDF 1.7 Extension Level 3 specification.

It contains a string representing a PDF name object.

This item may take one of the following valid values:.

• Navigation
• Event

For definitive details see:.

Adobe Supplement to the ISO 32000, BaseVersion: 1.7, ExtensionLevel: 3; Table: 9.51e, page 92.