Thai language support library

https://linux.thai.net/projects/libthai/

Theora video codec for the Ogg multimedia streaming system

https://www.theora.org/

Generic shared library support script

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

Lightweight fully POSIX compliant regexp matching library

https://laurikari.net/tre/

Integer-only fully Ogg Vorbis compliant decoder library

https://xiph.org/vorbis/

User space caching library

http://mercurial.creo.hu/repos/libublio

Library for manipulating Unicode characters and strings

https://www.gnome.org/

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

Multi-platform support library with a focus on asynchronous I/O

https://github.com/libuv/libuv

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

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/

Libraries for xine multimedia player

http://www.xine-project.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/