Qt QML and JavaScript language module

http://qt-project.org

Command line client to QStandardPaths

Qt declarative framework for dynamic user interfaces

http://qt-project.org

Set of controls for building complete interfaces in Qt Quick

https://qt-project.org

Set of controls for building complete interfaces in Qt Quick

https://qt-project.org

Qt 4-compatible scripting module

https://www.qt.io/

Qt Script additional components

https://www.qt.io/

Qt sensors module

https://www.qt.io/

Qt functions to access industrial bus systems

https://www.qt.io/

Qt functions to access serial ports

https://www.qt.io/

Qt SQL database integration module

https://www.qt.io/

Qt MySQL database plugin

https://www.qt.io/

Qt Open Database Connectivity plugin

https://www.qt.io/

Qt PostgreSQL database plugin

https://www.qt.io/

Qt SQLite 3 database plugin

https://www.qt.io/

Qt TDS Database Connectivity database plugin

https://www.qt.io/

Qt SVG support module

https://www.qt.io/

Qt unit testing module

https://www.qt.io/

Custom Qt widget plugin interface for Qt Designer

https://www.qt.io/

Qt Designer UI forms support module

https://www.qt.io/

Qt 5 library for integration of C++/QML with HTML/js clients

https://www.qt.io/

Qt implementation of WebSocket protocol

https://www.qt.io/

Qt C++ widgets module

https://www.qt.io/

Qt platform-specific features for X11-based systems

https://www.qt.io/

Qt SAX and DOM implementations

https://www.qt.io/

Qt support for XPath, XQuery, XSLT and XML Schema

https://www.qt.io/

Quake III Arena data files

http://www.idsoftware.com/games/quake/quake3-arena/

Command line tool for parsing flash media stream URLs

http://quvi.sourceforge.net/

Qt 4 wrapper library around the Zeitgeist D-Bus API

http://zeitgeist-project.com

RabbitMQ is an implementation of AMQP

http://www.rabbitmq.com/

RabbitMQ C AMQP client library

https://github.com/alanxz/rabbitmq-c

Test performance of storage devices

Cache and memory benchmarking tool

http://alasir.com/software/ramspeed/

Randr extension headers

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

RDF Parser Toolkit for Redland

http://librdf.org/raptor/

RDF Parser Toolkit for Redland

https://librdf.org/raptor/

File archiver (binary port)

https://www.rarlab.com/

OMF help system based on the Freedesktop specification

https://rarian.freedesktop.org/

High-level interface for RDF

http://librdf.org/

Simple window manager with no fat library dependencies

https://www.nongnu.org/ratpoison/

Distributed, collaborative, spam detection and filtering network

http://razor.sourceforge.net/

Unix incarnation of the plan9 shell

http://tobold.org/article/rc

Checks rc scripts for style and common errors

https://github.com/crees/rclint

Version control system (as was in FreeBSD prior to removal)

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

RDP client for Windows NT/2000/2003 Terminal Server

http://www.rdesktop.org/

Fast C++ regex library

https://github.com/google/re2

Lexer generator for C, C++ and Go with a focus on generating fast code

https://re2c.org/

Library for editing command lines as they are typed

https://tiswww.case.edu/php/chet/readline/rltop.html

Converts files between character sets and usages

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

RECORD extension headers

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