Binary package “ghostscript-doc” in ubuntu bionic

interpreter for the PostScript language and for PDF - Documentation

 GPL Ghostscript is used for PostScript/PDF preview and printing.
 Usually as a back-end to a program such as ghostview, it can display
 PostScript and PDF documents in an X11 environment.
 .
 This package contains documentation for GPL Ghostscript, mainly
 targeted developers and advanced users.