Qt is a comprehensive, object-oriented development framework that enables development of high-performance, cross-platform rich-client and server-side applications. When you implement a program with Qt, you can run it on the X Window System (Unix/X11), Apple Mac OS X, and Microsoft Windows NT/9x/2000/XP by simply compiling the source code for the platform you want. Qt is the basis for the KDE desktop environment, and is also used in numerous commercial applications such as Google Earth, Skype for Linux, and Adobe Photoshop Elements.
RT is an industrial-grade trouble ticketing system. It lets a group of people intelligently and efficiently manage requests submitted by a community of users. RT is used by systems administrators, customer support staffs, NOCs, developers, and even marketing departments to track issues, outages, bugs, requests, and all kinds of other things at thousands of sites around the world.
NEdit is a Unix text editor for programmers and general users. It combines a standard, easy-to-use, graphical user interface with the thorough functionality and stability required by users who edit text eight hours a day. It includes a macro language with a complete library of editing functions, state-of-the-art syntax highlighting for 30 common languages and text processors, and the best mouse-interactivity available in a Unix text editor.
Mesa is a 3-D graphics library which uses the OpenGL API (Application Programming Interface). Mesa cannot be called an implementation of OpenGL since the author did not obtain an OpenGL license from SGI. Furthermore, Mesa cannot claim OpenGL conformance since the conformance tests are only available to OpenGL licensees. Despite these technical/legal terms, you may find Mesa to be a valid alternative to OpenGL. Most applications written for OpenGL can use Mesa instead without changing the source code.
GNOME is the GNU Network Object Model Environment. This project is building a complete, user-friendly desktop based entirely on free software. This desktop consists of small utilities and larger applications that share a consistent look and feel. It uses the GTK as the GUI toolkit for all GNOME-compliant applications.
For users on Linux and Unix, KDE offers a full suite of user workspace applications which allow interaction with these operating systems in a modern, graphical user interface. This includes Plasma Desktop, KDE's innovative and powerful desktop interface. Other workspace applications are included to aid with system configuration, running programs, or interacting with hardware devices. While the fully integrated KDE Workspaces are only available on Linux and Unix, some of these features are available on other platforms. In addition to the workspace, KDE produces a number of key applications such as the Konqueror Web browser, Dolphin file manager, and Kontact, the comprehensive personal information management suite. The list of applications includes many others, including those for education, multimedia, office productivity, networking, games, and much more. Most applications are available on all platforms supported by the KDE Development. KDE also brings to the forefront many innovations for application developers. An entire infrastructure has been designed and implemented to help programmers create robust and comprehensive applications in the most efficient manner, eliminating the complexity and tediousness of creating highly functional applications.
GTK, which stands for the Gimp ToolKit, is a library for creating graphical user interfaces. It is designed to be small and efficient, but still flexible enough to allow the programmer freedom in the interfaces created. GTK provides some unique features over standard widget libraries.
Wine is an implementation of the Windows API on top of X and Unix. It does not require Microsoft Windows, but can use native Windows DLLs if they are available. It provides both a development toolkit for porting Windows source code to Unix as well as a program loader, allowing many unmodified Windows programs to run on x86-based Unixes.