Allows you to check the value of the trapped flag in a PDF.
The trapped flag indicates whether or not a file has been "trapped", i.e. has been corrected for slight color misregistrations. The trapped flag must be defined in PDF/X documents.
The trapped flag is stored in the info dictionary and/or in the XMP metadata stream, but the data can be inconsistent; that's why you must indicate where the trapped flag must be taken from, e.g. from the most recent metadata location.