Lossless compression for bi-level images such as scanned pages, faxes

https://www.cl.cam.ac.uk/~mgk25/jbigkit/

Converts JFile database to CSV, and vice versa

http://www.land-j.com/jfileu.html

Jerry's command-line LiveJournal.com entry system

http://umlautllama.com/projects/perl/#jlj

IJG's jpeg compression utilities

http://www.ijg.org/

The editor which sucks less

http://www.mirbsd.org/jupp.htm

KB extension headers

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

Script which hooks into startkde and helps KDE pick up XDG apps/menus

The Oxygen icon theme for KDE

http://www.kde.org

Script which hooks into startkde and helps KDE pick up XDG apps/menus

Utility port which installs a hierarchy of shared KDE directories

Hierarchy of shared KDE4 directories

Serial and network communications package

https://www.kermitproject.org/

Cracks SAMBA or Windows NT passwords

Microsoft .CABinet file creator

http://ohnopub.net/~ohnobinki/lcab/

Light Color Management System -- a color management library

http://www.littlecms.com/

Accurate, fast, and small-footprint color management engine

https://www.littlecms.com/

Ldconfig compatibility script

LALR(1) parser generator. Similar in function to yacc and bison

https://www.hwaci.com/sw/lemon/

Better pager utility

https://www.greenwoodsoftware.com/less/

Archive files using LZSS and Huffman compression (.lzh files)

http://www2m.biglobe.ne.jp/~dolphin/lha/lha.htm

Archive files using LZSS and Huffman compression (.lzh files)

https://lha.osdn.jp

The FS library

https://www.x.org/

Inter Client Exchange library for X11

https://www.freedesktop.org/wiki/Software/xlibs/

Session Management library for X11

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

Authentication Protocol library for X11

https://www.freedesktop.org/wiki/Software/xlibs/

X Display Manager Control Protocol library

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

Portable audio output library

https://www.xiph.org/ao/

Library for high-performance 2D graphics

http://www.levien.com/libart/

Sound library for SGI audio file

http://www.68k.org/~michael/audiofile/

Standard C resolver library

https://www.isc.org/software/libbind

Libburnia library to read/write optical discs

https://dev.lovelyhq.com/libburnia/web/wikis/home

Library for playing audio CDs

http://libcdaudio.sourceforge.net/

Library to access data on a CDDB server

http://libcddb.sourceforge.net/

Lightweight C library that eases the writing of UNIX daemons

http://0pointer.de/lennart/projects/libdaemon/

Free DTS Coherent Acoustics decoder

https://www.videolan.org/developers/libdca.html

Library for creating MusicBrainz DiscIDs

http://musicbrainz.org/doc/libdiscid

Alsa compatibility library to build DSSI

http://www.smbolton.com/linux.html

Enhanced Metafile Library

http://libemf.sourceforge.net/

Full-featured and high-performance event loop library

http://software.schmorp.de/pkg/libev.html

API for executing callback functions on events or timeouts

https://libevent.org/

API for executing callback functions on events or timeouts

http://libevent.org/

Library for inspecting program's backtrace

http://www.gnu.org/software/libc/manual/html_node/Backtraces.html

Video encoding library

http://fame.sourceforge.net/

Foreign Function Interface

https://sourceware.org/libffi/

The fontenc Library

https://www.x.org/

Library routines for working with Flashpix images

https://www.i3a.org/

Programming reference for print/libgnomeprint

http://www.gnome.org/projects/gnome-print/

ID3 tags library (part of MAD project)

http://mad.sourceforge.net/

Kevent based inotify compatible library

https://github.com/libinotify-kqueue/libinotify-kqueue

Standalone client/server 9P library

https://libs.suckless.org/deprecated/libixp/