Represents the "MN" entry of the printer's mark annotation object.

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

It contains a string representing a PDF name object.

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 362, page 632.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 398, page 812.

The MN entry holds a name identifying the type of printer mark. Prepress tools use this to locate specific marks by name without analysing their appearance streams.