This version is Aladdin copyright, not GNU copyleft, see /usr/doc/gs-aladdin/copyright.
Ghostscript is used for postscript preview and printing. Usually as a back-end to a program such as ghostview, it can display postscript documents in an X11 environment. It can also use the Linux svga library to display documents graphically on the Linux console.
Furthermore, it can render postscript files as graphics to be printed on non-postscript printers. Supported printers include common dot-matrix, inkjet and laser models.
Package gsfonts contains a set of standard fonts for ghostscript.
You have to install the gs-pdfencrypt package to be able to preview encrypted pdf files. That package is in the nonus distribution due to the stupid US regulations about exporting cryptographic software (please look under ftp://nonus.debian.org/pub/debian-non-US to find it).
The Ghostscript World Wide Web home page is at http://www.cs.wisc.edu/~ghost/index.html
This package also contains the hpdj driver contributed by Martin Lottermoser.