Improved spell-checker for Hungarian and other languages

https://hunspell.github.io/

Portable Hardware Locality software package

https://www.open-mpi.org/projects/hwloc/

IA64 simulator (Intel(R) Architecture 64)

http://www.boo.net/~jasonp/

Restricted unix shell

http://ibsh.sourceforge.net/

ICE authority file utility for X

Displays a wire-frame rotating plyhedron

https://gitlab.freedesktop.org/xorg/app/ico

Utilities of the Tango project

http://tango-project.org/

International Components for Unicode (from IBM)

https://icu.unicode.org/

Library to handle internationalized domain names

https://www.nic.ad.jp/ja/idn/idnkit/download/

Internet Low Bit Rate codec (RFC3951)

http://www.ilbcfreeware.org/

ILM Base libraries a.k.a. Half, IlmThread, Imath, and Iex

http://www.openexr.com/

Imake and other utilities from X.Org

https://www.x.org/

Publishing and presentation tool

https://www.ntlug.org/~ccox/impress/

Utility to regenerate the GNU info page index

https://github.com/bapt/indexinfo

Input extension headers

Tools to internationalize various kinds of data files

http://www.gnome.org/

Performance Test of Sequential File I/O

https://www.iozone.org/

Performance Test of Sequential File I/O (older version)

https://www.iozone.org/

Tool to measure maximum TCP and UDP bandwidth

https://sourceforge.net/projects/iperf2/

KAME racoon IKE daemon, ipsec-tools version

http://ipsec-tools.sourceforge.net/

Modular IRC client with many features

https://irssi.org/

Collection of useful scripts for the irssi IRC-client

https://scripts.irssi.org/

Collection of additional irssi themes

https://irssi-import.github.io/themes/

ISC Cron, former Vixie Cron

ftp://ftp.isc.org/isc/cron/

Converts documents from text/HTML to iSilo format

http://www.iSilo.com/

Lists of the country, language, and currency iso names

https://salsa.debian.org/iso-codes-team/iso-codes

Character entity sets from ISO 8879:1986 (SGML)

Make XML documents translatable through po files

https://itstool.org/

Object-oriented SGML/XML parser toolkit and DSSSL engine

http://www.jclark.com/jade/

C library for encoding, decoding, and manipulating JSON data

https://github.com/akheron/jansson

Implementation of the codec specified in the JPEG-2000 standard

https://www.ece.uvic.ca/~frodo/jasper/

Updated Java timezone definitions

Wrapper script for various Java Virtual Machines

Decoder implementation of the JBIG2 image compression format

https://github.com/ArtifexSoftware/jbig2dec

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

Java source to byte-code compiler made available by IBM

http://jikes.sf.net/

Jerry's command-line LiveJournal.com entry system

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

Joe's Own Editor

https://sourceforge.net/projects/joe-editor/

IJG's jpeg compression utilities

http://www.ijg.org/

JSON (RFC 4627) interface for Glib

http://live.gnome.org/JsonGlib

General purpose dynamic array

https://judy.sourceforge.net/

The editor which sucks less

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

Makefile framework

https://svn.netlabs.org/kbuild

KB extension headers

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

Portable scriptable network and serial communication program

https://www.kermitproject.org/

802.11 layer2 wireless network detector, sniffer, and IDS

https://www.kismetwireless.net/

MIT implementation of RFC 4120 network authentication service

https://web.mit.edu/kerberos/

Cracks SAMBA or Windows NT passwords

Linux Audio Developer's Simple Plugin API

https://www.ladspa.org/