Represents the "RoleMapNS" entry of the namespace dictionary object.

It is an optional entry defined as part of the PDF 2.0 specification.

It contains an Element.

For definitive details see:.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 356, page 725.

The RoleMapNS entry holds a dictionary mapping element type names in this namespace to standard PDF structure type names, allowing readers that do not support the namespace to apply standard semantics.