Lightweight DNS forwarder, DHCP, and TFTP server

http://www.thekelleys.org.uk/dnsmasq/doc.html

Simple sudo alternative to run commands as another user

https://github.com/slicer69/doas/

Meta-port for the different versions of the DocBook DTD

http://www.oasis-open.org/docbook/

DocBook SGML DTD

http://www.oasis-open.org/docbook/

DocBook SGML DTD into nroff/troff -man macros converter

https://www.oasis-open.org/docbook/tools/dtm/

Generates various output formats from DocBook SGML documents

http://sources.redhat.com/docbook-tools/

DocBook XML DTD

https://www.oasis-open.org/docbook/

DocBook W3C XML Schema

https://www.oasis-open.org/docbook/xmlschema/1.0b1/

XSL DocBook stylesheets

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

Namespace-aware DocBook XSLT stylesheets

http://docbook.sourceforge.net

Convert DocBook refentry to mdoc

https://mandoc.bsd.lv/docbook2mdoc/

Emacs lisp modules for editing DocBook documents

http://nwalsh.com/emacs/docbookide/

C++11 options parser based on help messages

https://github.com/docopt/docopt.cpp

Command-line DNS client

https://dns.lookup.dog/

DNS-over-HTTP server proxy

https://github.com/jedisct1/rust-doh

Open-source DHTML toolkit written in JavaScript

https://dojotoolkit.org/

Doom data files (Doom, Doom II, Hexen, Heretic and Strife)

Complete Doom-based game IWAD that is Free Software

http://freedoom.sf.net/

Improved and extended version of Doom

http://doomlegacy.sourceforge.net/

DOS/Mac to Unix and vice versa text file format converter

https://waterlan.home.xs4all.nl/dos2unix.html

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/

Library for compressing and decompressing 3D meshes and point clouds

https://google.github.io/draco/

Diagramming and whiteboarding desktop app

https://drawio.com/

DRM drivers modules

https://github.com/freebsd/drm-kmod/

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/

Qt client for DSBMD that lets you mount media, and more

https://github.com/mrclksr/DSBMC

Command-line client for DSBMD

https://freeshell.de/~mk/projects/dsbmc-cli.html

Media mounting daemon

https://github.com/mrclksr/DSBMD

API for audio processing plugins

http://dssi.sourceforge.net/

DSSSL stylesheets for the DocBook DTD by Norman Walsh

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

Belegloser DatenTraegerAUStausch

https://www.infodrom.org/projects/dtaus/

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

DVD burning software

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

Makes a DVD file structure from one or more MPEG2 streams

https://dvdauthor.sourceforge.net/ https://github.com/ldo/dvdauthor

Backup content from DVD to hard disk

http://dvdbackup.sourceforge.net/