Platform-neutral API for system level and libc like functions

https://developer.mozilla.org/docs/Mozilla/Projects/NSPR

Libraries to support development of security-enabled applications

https://developer.mozilla.org/docs/Mozilla/Projects/NSS

RFC 2307 NSS module

http://www.padl.com/OSS/nss_ldap.html

Not so Trivial DataBase

http://tdb.samba.org/

The Network Time Protocol Distribution

https://www.ntp.org/

Client/server program for testing network performance

Another font package for X

Turns on numlock in X

http://home.kde.org/~seli/numlockx/

Nutrition software to record what you eat

http://nut.sourceforge.net/

nVidia graphic card status and overclocking tool

http://www.linuxhardware.org/nvclock/

Development snapshot of the world-renown nvi editor

http://www.kotnet.org/~skimo/nvi/

NVidia graphics card binary drivers for hardware OpenGL rendering

https://www.nvidia.com/object/unix.html

Display Control Panel for X NVidia driver

http://www.nvidia.com/object/unix.html

Texture Tools with support for DirectX 10 texture formats

https://github.com/castano/nvidia-texture-tools

Tool to manipulate X configuration files for the NVidia driver

http://www.nvidia.com/object/unix.html

Nils Weller's BSD-licensed C-compiler

http://nwcc.sourceforge.net/

Standalone converter for the OpenOffice.org writer and scalc formats

http://siag.nu/o3read/

Preferences manager for the Openbox window manager

http://openbox.org/wiki/Obconf

Securely delete file[s]

Objective Caml compiler and programming environment

https://ocaml.org/

Autoconf module for ocaml

http://forge.ocamlcore.org/projects/ocaml-autoconf/

Objective Caml compiler and programming environment (no X11)

https://ocaml.org/

OpenCL Installable Client Driver

https://github.com/OCL-dev/ocl-icd

Round clock application for X

OCR program implemented as filter

http://www.gnu.org/software/ocrad/ocrad.html

Customized version of the Source Code Pro font

https://github.com/nathco/Office-Code-Pro

Monospaced font based on Artwiz Snap

https://sourceforge.net/projects/osnapfont/

Help you update your snort rules after each update

http://oinkmaster.sourceforge.net/

Ultimate Oldschool PC Font Pack

http://int10h.org/oldschool-pc-fonts/

Regular expressions library compatible with POSIX/GNU/Perl

https://github.com/kkos/oniguruma

VoIP abstraction library

http://opalvoip.org/

Open-source COBOL compiler

http://www.opencobol.org/

Motif X11 Toolkit (industry standard GUI (IEEE 1295))

https://motif.ics.com/

Clean and modern sans-serif typeface

https://www.opensans.com

Open VMware tools for MidnightBSD VMware guests

https://github.com/vmware/open-vm-tools

Open VMware tools for FreeBSD VMware guests

https://github.com/vmware/open-vm-tools

3D positional spatialized sound library

http://www.openal.org/

Software implementation of the OpenAL specification

http://kcat.strangesoft.net/openal.html

Chemical toolbox designed to speak the many languages of chemical data

https://openbabel.org/wiki/Main_Page

Optimized BLAS library based on GotoBLAS2

https://github.com/xianyi/OpenBLAS

Small, fast, standards compliant, extensible window manager

http://openbox.org/

Open Crypto Development Kit

http://www.gnutls.org/

Open Computing Language (OpenCL) specifications V3.0 (header files)

https://github.com/KhronosGroup/OpenCL-Headers/

OpenCORE implementation of AMR Narrowband & Wideband speech codec

http://sourceforge.net/projects/opencore-amr/

Middleware framework for smart card terminals

https://github.com/OpenSC/openct

Open Source Computer Vision library

https://www.opencv.org/

Open Source Computer Vision library

https://www.opencv.org/

DKIM library and milter implementation

http://opendkim.org/

High dynamic-range (HDR) image file format

https://github.com/AcademySoftwareFoundation/openexr/

Enterprise instant messaging server

https://www.igniterealtime.org/projects/openfire/index.jsp