Library of Unicode annotation data

http://libuninameslist.sourceforge.net/

Library for converting Unicode strings to numbers

http://billposer.org/Software/libuninum.html

Unicode string library

https://www.gnu.org/software/libunistring/

Library to work with RAR archivies

http://www.rarsoft.com/

Communication interface library for usbmuxd

http://www.libimobiledevice.org

The uTorrent Transport Protocol library and sample utilities

https://github.com/bittorrent/libutp

Video4Linux library

https://linuxtv.org/wiki/index.php/V4l-utils

VAAPI wrapper and dummy driver

https://github.com/intel/libva

VDPAU wrapper and tracing library

http://freedesktop.org/wiki/Software/VDPAU

Abstraction library that sits between apps and visual plugin

http://libvisual.sourceforge.net/

Provide an easy API to a custom vnc server

http://libvnc.github.io/

Library to provide file system type information

Audio compression codec library

https://xiph.org/vorbis/

VP8/VP9 reference encoder/decoder

https://www.webmproject.org/

Tools and library for converting Microsoft WMF (windows metafile)

http://wvware.sourceforge.net/libwmf.html

Library used for writing pagers and taskslists

https://www.gnome.org/

Library used for writing pagers and taskslists

http://www.gnome.org/

Tools for importing and exporting WordPerfect(tm) documents

http://libwpd.sourceforge.net/

Window Maker raster graphics library

http://www.windowmaker.org/

The W3C Reference Library

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

Library for encoding H.264/MPEG-4 AVC video

http://www.videolan.org/x264.html

The X protocol C-language Binding (XCB) library

https://xcb.freedesktop.org/

Implementation of the XDG Base Directory specification

https://github.com/devnev/libxdg-basedir/

Various Gtk widgets for the Xfce Desktop

http://www.xfce.org/

Widgets library for the Xfce desktop environment

https://www.xfce.org/

Extension library for the Xfce desktop environment

https://www.xfce.org/

Keymap handling library for toolkits and window systems

https://xkbcommon.org/

XKB file library

https://www.freedesktop.org/Software/xorg

The xkbui library

http://www.freedesktop.org/Software/xorg

Utility library to make XKB stuff easier

http://gswitchit.sourceforge.net/

XML API for C++

http://libxmlplusplus.sourceforge.net/

XML parser library for GNOME

http://xmlsoft.org/

Shared memory 'SyncFence' synchronization primitive

http://www.freedesktop.org/Software/xlibs

The XSLT C library for GNOME

http://xmlsoft.org/XSLT/

YAML 1.1 parser and emitter written in C

https://pyyaml.org/wiki/LibYAML

C library for reading, creating, and modifying ZIP archives

https://libzip.org/

GNU ZRTP library

https://github.com/wernerd/ZRTPCPP

Routines to access raw VBI capture devices

http://zapping.sourceforge.net/doc/libzvbi/

Secure, fast, compliant, and flexible Web Server

https://www.lighttpd.net/

Library for writing networked servers & clients

http://www.gnome.org/

Rich city simulation game for X

http://lincity.sourceforge.net/

Lynx-like text WWW browser

http://links.twibright.com/

Lynx-like text WWW browser

http://www.jikos.cz/~mikulas/links/

The Adobe SVG browser plugin (Linux version)

http://www.adobe.com/svg/

Wolfenstein: Enemy Territory (Linux version)

https://www.splashdamage.com/games/wolfenstein-enemy-territory/

ET Pro - The Enemy Territory Competition Mod

http://etpro.anime.net/

ET Pub - An Enemy Territory Modification

http://et.tjw.org/etpub/

A class-based teamplay modification for Enemy Territory

http://www.etfgame.com/

Jaymod - An Enemy Territory Modification

http://jaymod.clanfu.org/

Omni-Bot is a bot for Enemy Territory

http://www.omni-bot.de/