Documentation system for C, C++, and other languages

https://www.doxygen.org/

DRI2 prototype headers

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

DSSSL stylesheets for the DocBook DTD by Norman Walsh

http://sourceforge.net/projects/docbook/

DVD burning software

http://fy.chalmers.se/~appro/linux/DVD+RW/

Backup content from DVD to hard disk

http://dvdbackup.sourceforge.net/

Blkid library from e2fsprogs package

http://e2fsprogs.sourceforge.net/

UUID library from e2fsprogs package

http://e2fsprogs.sourceforge.net/

Small RSA key management package based on openssl

https://github.com/OpenVPN/easy-rsa

Accessing and converting various ebook file formats

https://sourceforge.net/projects/ebook-tools/

Lightweight library for vector and matrix math

http://eigen.tuxfamily.org/

Lightweight library for vector and matrix math

http://eigen.tuxfamily.org/

Lightweight library for vector and matrix math

http://eigen.tuxfamily.org/

ASCII to PostScript filter

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

ASCII to PostScript filter

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

Extensible shell, derived from plan9's rc

http://wryun.github.io/es-shell/

The "easy shell", a small shell with Lisp-like syntax

Software speech synthesizer

http://espeak.sourceforge.net/

XEVIE extension headers

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

Exif, IPTC, and XMP metadata manipulation library and tools

https://www.exiv2.org/

XML 1.0 parser written in C

https://github.com/libexpat/libexpat

Partition-selectable boot loader for IBM-PC/AT compatibles

http://extipl.sourceforge.jp/

Tool for extracting and creating optimised Xbox ISO images

http://sourceforge.net/projects/extract-xiso/

Update your host name on any dynamic DNS service

http://www.ez-ipupdate.com/

Framework to easily create, manipulate, and run BSD jails

http://erdgeist.org/arts/software/ezjail/

Fortran-to-C converter and its run-time libraries

http://www.netlib.org/

version of JDK's `jar' command written entirely in C

http://fastjar.sourceforge.net/

CUI-based file and directory management tool

https://hp.vector.co.jp/authors/VA012337/soft/fd/

Batch mail retrieval utility for IMAP/POP3/ETRN/ODMR

https://www.fetchmail.info/

Foreign function call libraries

http://www.haible.de/bruno/packages-ffcall.html

Utility to recover UFS2 filesystems

https://BSDforge.com/projects/sysutils/ffs2recov/

Fast C routines to compute the Discrete Fourier Transform

http://www.fftw.org/

Fast Discrete Fourier Transform (Single Precision C Routines)

http://www.fftw.org/

Integrated benchmark program

http://tromp.github.io/c4/fhour.html

GNU find utilities

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

Wrapper scripts for firefox web browser

Remote firewall auditing tool

http://www.packetfactory.net/firewalk/

Fixes extension headers

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

Patch making it possible to embed PNGs into RTFs

Free lossless audio codec

https://www.xiph.org/flac/

Backup content from any volume to a tarball

https://github.com/laffer1/flashback/

Fast lexical analyzer generator

https://github.com/westes/flex

Small run-time speech synthesis engine

http://www.festvox.org/flite/

Manage locks from shell scripts

https://www.kernel.org/pub/linux/utils/util-linux/

Floating point benchmark to give your MFLOPS rating

http://performance.netlib.org/performance/html/flops.html

Legacy FreeBSD pmake

Create an index of X font files in a directory

https://www.x.org/

Fontcache extension headers

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

XML-based font configuration API for X Windows

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

Fonts extension headers

http://www.x.org/

Database for integrating printer drivers with common spoolers

http://www.linuxfoundation.org/collaborate/workgroups/openprinting/database/foomatic