Represents the "AF" entry of the catalog dictionary object.

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

It contains an array which contains FileSpecificationElements.

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 28, page 73.

Adobe Supplement to the ISO 32000, BaseVersion: 1.7, ExtensionLevel: 3; Table: 3.25, page 23.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 29, page 101.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 242, page 458.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 245, page 555.

The AF entry in the catalog holds an array of file specification dictionaries for files associated with the document as a whole. This is the document-level associated files mechanism used in PDF/A-3 and PDF 2.0 workflows.