Checks if the unicode mappings of the fonts are compliant with a particular PDF/A version.
PDF/A requires that all text in the PDF file can be mapped to Unicode. Therefore, fonts used in the PDF should contain a character-to-glyph mapping that is consistent with character semantics as defined in the Unicode Standard.
This mapping is used to override the default text extraction behavior, for example when using the Acrobat text tool to copy and paste text to another application like Notepad.