This class represents the optional content usage page dictionary. This is definitively detailed in:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 102, page 232.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 100, page 284.

The page element usage dictionary marks an optional content group as representing a structural page element type, such as a running header, footer, or watermark.

The Subtype entry names the element type. Layout applications use this information to identify and manage recurring structural components across pages.

System.Object
    WebSupergoo.ABCpdf14.Elements.Element
       WebSupergoo.ABCpdf14.Elements.OptionalContentUsagePageElement