Complete Doom-based game IWAD that is Free Software

http://freedoom.sf.net/

Improved and extended version of Doom

http://doomlegacy.sourceforge.net/

Emulator of a PC with DOS

http://dosbox.sourceforge.net/

Simple, powerful configuration-file parser

https://github.com/williamh/dotconf

Binary-decimal and decimal-binary routines for IEEE doubles

https://github.com/google/double-conversion

Doulos SIL TrueType font collection

http://scripts.sil.org/cms/scripts/page.php?item_id=DoulosSILfont

Doulos SIL TrueType font collection, compact variant

http://scripts.sil.org/cms/scripts/page.php?item_id=DoulosSILfont

Secure, fast and powerful IMAP and POP3 server

https://www.dovecot.org/

Sieve plugin for the Dovecot 'deliver' LDA and LMTP

https://wiki2.dovecot.org/Pigeonhole

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

https://www.doxygen.org/

DRM modules for the linuxkpi-based KMS components

https://github.com/FreeBSDDesktop/kms-drm

The Droid typeface family

https://www.droidfonts.com/

Database driven web content management system (CMS)

https://www.drupal.org/

Database driven web content management system (CMS)

https://www.drupal.org/

Database driven web content management system (CMS)

https://www.drupal.org/

DSSSL stylesheets for the DocBook DTD by Norman Walsh

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

Device Tree Compiler

https://git.kernel.org/cgit/utils/dtc/dtc.git

Spawns dhclients for a dual-stack network

Embeddable Javascript engine

https://duktape.org/

Embeddable Javascript engine (shared lib)

https://duktape.org/

Python implementation of the Git file formats and protocols

https://www.dulwich.io/

English to Thai dictionary for GNUstep

http://www.eskimo.com/~pburns/Dictionaries/

Duo unix integration package

http://duosecurity.com

Backup tool that uses librsync and GnuPG

http://duplicity.nongnu.org

Shell front end for the duplicity backup tool

http://duply.net

DVD burning software

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

Backup content from DVD to hard disk

http://dvdbackup.sourceforge.net/

Utilities & library to manipulate ext2/3/4 filesystems

http://e2fsprogs.sourceforge.net/

Blkid library from e2fsprogs package

http://e2fsprogs.sourceforge.net/

Command-line interface parsing library from e2fsprogs

UUID library from e2fsprogs package

http://e2fsprogs.sourceforge.net/

EFL DBUS connectivity library

http://docs.enlightenment.org/api/e_dbus/html/

Small RSA key management package based on openssl

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

GNUstep graphical diff

Accessing and converting various ebook file formats

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

Startup scripts for FreeBSD/EC2 environment

http://www.daemonology.net/freebsd-on-ec2/

Eclipse IDE 2020-06

https://www.eclipse.org/

Scientific calcultor for GNUstep

http://www.eskimo.com/~pburns/EdenMath/

Dynamic resource editor for X Toolkit Applications

Fax send/receive program

Enlightenment Foundation Libraries

https://docs.enlightenment.org/efl/current/

Speech server for Festival Lite used by yasr and Emacspeak

http://eflite.sourceforge.net/

D-Bus bindings for GObject

http://cgit.freedesktop.org/~david/eggdbus

EGL External Platform interface

https://github.com/NVIDIA/eglexternalplatform

Lightweight library for vector and matrix math

http://eigen.tuxfamily.org/

Lightweight library for vector and matrix math

http://eigen.tuxfamily.org/

VoIP and video conferencing application

https://www.ekiga.org/

Full-text search engine for Java

https://www.elastic.co/

Full-text search engine for Java

https://www.elastic.co/

Functional, meta-programming aware language built on top of Erlang VM

https://elixir-lang.org/