Represents the "PageElement" entry of the optional content usage dictionary object.

It is an optional entry defined as part of the PDF 1.0 specification.

It contains an OptionalContentUsagePageElement.

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 102, page 233.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 100, page 285.

The PageElement sub-dictionary marks this group as representing a specific structural page element type, such as a running header or footer. It contains a Subtype name identifying the element. Layout tools use this to manage repeating structural content.