Represents the "EF" entry of the full file specification dictionary object.

It is defined as part of the PDF 1.3 specification.

It contains an EmbeddedFileSetElement.

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 44, page 103.

Adobe Supplement to the ISO 32000, BaseVersion: 1.7, ExtensionLevel: 3; Table: 3.41, page 26.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 43, page 134.

The EF entry holds an embedded file set dictionary mapping path keys to embedded file stream references. When present, the file data is stored directly in the PDF rather than requiring access to an external file.