The W3C Reference Library is a general code base that can be used to build
clients and servers. It contains code for accessing HTTP, FTP, Gopher, News,
WAIS, Telnet servers, and the local file system. Furthermore it provides
modules for parsing, managing and presenting hypertext objects to the user
and a wide spectra of generic programming utilities. The Library is the
basis for many World-Wide Web applications and all the W3C software is build
on top of it. The Library is a required part of all other W3C applications
in this distribution.

WWW: http://www.w3.org/Library/