VNC stands for Virtual Network Computing. It is, in essence, a remote display system which allows you to view a computing `desktop' environment not only on the machine where it is running, but from anywhere on the Internet and from a wide variety of machine architectures.
This package provides a vncserver to which X clients can connect and the server generates a display that can be viewed with a vncviewer.
It contains an X server connector so clients can connect to your local X desktop directly.
Note: This server does not need a display. You need a vncviewer to see something. This viewer may also be on a computer running other operating systems.