Description:

Ghostscript is a set of software that provides a PostScript(TM) interpreter,
a set of C procedures (the Ghostscript library, which implements the
graphics capabilities in the PostScript language) and an interpreter for
Portable Document Format (PDF) files. Ghostscript translates PostScript code
into many common, bitmapped formats, like those understood by your printer
or screen. Ghostscript is normally used to display PostScript files and to
print PostScript files to non-PostScript printers.
Most applications use PostScript for printer output.

You should install ghostscript if you need to display PostScript files, or
if you have a non-PostScript printer.