Unreal - the next generation ircd

https://www.unrealircd.org/

FUSE-based fault injection filesystem

https://github.com/ligurio/unreliablefs

List, test, and extract compressed files from a ZIP archive

http://www.info-zip.org/UnZip.html

A zoo archive extractor

http://freecode.com/projects/unzoo/

Uptimes project client

https://upclient.sourceforge.net

Network performance tool to model and replay of networking patterns

https://uperf.org/

Universal Plug and Play Software Development Kit

http://pupnp.sourceforge.net/

D-Bus daemon for simplifying power management tasks

http://upower.freedesktop.org/

The Ultimate Packer for eXecutables

http://upx.sourceforge.net/

URI parsing library

http://uriparser.sourceforge.net/

URL extractor/launcher

https://github.com/sigpipe/urlview

URW core35 fonts in various formats

https://www.ghostscript.com

Another font package for X

Unicode TrueType fonts from URW extended by Valek Filippov

USB HID device dumping utility

https://github.com/DIGImend/usbhid-dump

Database of all known IDs used in USB devices

http://www.linux-usb.org/

Daemon for multiplexing connections over USB to iPhone/iPod Touch

http://www.libimobiledevice.org

Utility for listing USB devices

https://github.com/gregkh/usbutils

Simple, portable, lightweight library for handling UTF-8 strings

http://utfcpp.sourceforge.net/

UTF-8 processing library

http://julialang.org/utf8proc/

hash table for C structures

http://uthash.sourceforge.net/

Kernel driver for absolute USB HID mice

https://github.com/wulf7/utouch

Program for uu/xx/Base64/BinHex/yEnc de-/encoding

http://www.fpx.de/fp/Software/UUDeview/

A library for uu/xx/Base64/BinHex/yEnc de-/encoding

http://www.fpx.de/fp/Software/UUDeview/

Monospaced bitmap fonts for X11

https://people.mpi-inf.mpg.de/~uwe/misc/uw-ttyp0/

Video4Linux utilities

http://freshmeat.net/projects/libv4l

Video4Linux IOCTL header files

Implementation of the UNIX 7th Edition shell

http://minnie.tuhs.org/UnixTree/V7/

Open source JavaScript engine by Google

http://code.google.com/p/v8/

Programming language and compiler that converts Vala code into C code

http://live.gnome.org/Vala

Memory debugging and profiling tool

https://bitbucket.org/stass/valgrind-freebsd/overview

Markup Validation Service from the World Wide Web Consortium (W3C)

http://validator.w3.org/

High-performance data structure server that primarily serves key/value workloads

https://valkey.io/

Vamp audio analysis plugin SDK

https://www.vamp-plugins.org/

Video processing framework with simplicity in mind

https://www.vapoursynth.com/

Varnish Module (vmod) for accessing maxminddb geoip data

https://github.com/simonvik/libvmod_maxminddb

High-performance HTTP accelerator

https://varnish-cache.org/

Simple Persian/Arabic font

https://rastikerdar.github.io/vazirmatn/

Open source Gameboy Advance emulator

http://vba.ngemu.com/

GNU VCDImager/VCDRip -- The GNU VideoCD Image Maker/Ripping Tool

http://www.gnu.org/software/vcdimager/

Library for manipulation of triangle meshes

https://github.com/cnr-isti-vclab/vcglib

User-mode virtual ethernet infrastructure

https://github.com/virtualsquare/vde-2

NTHU-CS Maple BBS 2.36 BBS-like editor

http://netlab.cse.yzu.edu.tw/~statue/freebsd/zh-tut/ve.html

Merchant Of Venice, a stock market trading program

http://mov.sourceforge.net/

Virtual Entity of Relevant Aconyms (EPWING V1 format)

http://openlab.ring.gr.jp/edict/fpw/

French verb conjugator/deconjugator

http://sarrazip.com/dev/verbiste.html

Synthesizable Verilog to C++ compiler

https://www.veripool.org/projects/verilator/wiki/Intro

PCB (printed circuit board) design software

https://sourceforge.net/projects/veroroute/

Virtual Ethernet Interface

https://github.com/hmatyschok/if_vether

Virtual font kit (n2a,a2n,a2bk,p2pn)