This class represents the catalog uri dictionary. This is definitively detailed in:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 207, page 424.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 211, page 515.

System.Object
    WebSupergoo.ABCpdf14.Elements.Element
       WebSupergoo.ABCpdf14.Elements.CatalogUriElement

A catalog URI dictionary supplies a base URI for the document. Relative URIs in URI actions are resolved against this base, allowing a set of links to be updated by changing only the catalog URI base.