Internal Ghostscript-Version GPL Ghostscript 9.21 (2017-03-16)

Source: http://downloads.ghostscript.com/public/ghostscript-9.21.tar.gz

Ghostscript can read a PostScript or PDF file and display the results on the
screen or convert them into a form you can print on a non-PostScript printer.
Especially together with several popular previewers, with Ghostscript
you can view or print an entire document or even isolated pages,
even if your computer doesn't have Display PostScript and your printer
doesn't handle PostScript itself.