KDE in the context of Free software movement

A graphical user interface, or GUI, is a form of user interface that allows users to interact with electronic devices through graphical icons and visual indicators such as secondary notation. In many applications, GUIs are used instead of text-based UIs, which are based on typed command labels or text navigation. GUIs were introduced in reaction to the perceived steep learning curve of command-line interfaces (CLIs), which require commands to be typed on a computer keyboard.

The actions in a GUI are usually performed through direct manipulation of the graphical elements. Beyond computers, GUIs are used in many handheld mobile devices such as MP3 players, portable media players, gaming devices, smartphones and smaller household, office and industrial controls. The term GUI tends not to be applied to other lower-display resolution types of interfaces, such as video games (where head-up displays (HUDs) are preferred), or not including flat screens like volumetric displays because the term is restricted to the scope of 2D display screens able to describe generic information, in the tradition of the computer science research at the Xerox Palo Alto Research Center.

WebKit is a browser engine primarily used in Apple's Safari web browser, as well as all web browsers on iOS and iPadOS. WebKit is also used by the PlayStation consoles starting with the PS3, the Tizen mobile operating systems, the Amazon Kindle e-book reader, Nintendo consoles starting with the 3DS Internet Browser, GNOME Web, and the discontinued BlackBerry Browser.

WebKit started as a fork of the KHTML and KJS libraries from KDE, and has since been further developed by KDE contributors, Apple, Google, Nokia, Bitstream, BlackBerry, Sony, Igalia, and others. WebKit supports macOS, Windows, Linux, and various other Unix-like operating systems. On April 3, 2013, Google announced that it had forked WebCore, a component of WebKit, to be used in future versions of Google Chrome under the name Blink. Since version 15 in May 2013, Opera web browser has dropped its own Presto layout engine in favor of WebKit as implemented by Google in the Chromium project.

KHTML is a discontinued browser engine that was developed by the KDE project. It originated as the engine of the Konqueror browser in the late 1990s, but active development ceased in 2016. It was officially discontinued in 2023.

Built on the KParts framework and written in C++, KHTML had relatively good support for Web standards during its prime. Engines forked from KHTML are used by most of the browsers that are widely used today, including WebKit (Safari) and Blink (Google Chrome, Chromium, Microsoft Edge, Opera, Vivaldi, Opera GX, Opera Mini, Opera Mobile, Yandex Browser, Orion, Arc (On iOS), Epiphany, Midori, Konqueror, Otter Browser, Dooble, Epic Privacy Browser, Slimjet, Comodo Dragon, SRWare Iron, Cốc Cốc, Torch Browser, Orbitum, UC Browser, Kiwi Browser, Samsung Internet, Bromite, Blisk, Colibri Browser, Min Browser, Ungoogled Chromium, Iridium Browser, Avast Secure Browser, AVG Secure Browser and Brave).

A thumbnail is a reduced-size version of a picture or video, used to help in recognizing and organizing them, serving the same role for images as a normal text index does for words. In the age of digital images, visual search engines and image-organizing programs normally use thumbnails, as do most modern operating systems or desktop environments, such as Microsoft Windows, macOS, KDE (Linux) and GNOME (Linux). On web pages, they also avoid the need to download larger files unnecessarily.

A Linux distribution, often abbreviated as distro, is an operating system that includes the Linux kernel for its kernel functionality. Although the name does not imply product distribution per se, a distro—if distributed on its own—is often obtained via a website intended specifically for the purpose. Distros have been designed for a wide variety of systems ranging from personal computers (for example, Linux Mint) to servers (for example, Red Hat Enterprise Linux) and from embedded devices (for example, OpenWrt) to supercomputers (for example, Rocks Cluster Distribution).

A distro typically includes many components in addition to the Linux kernel. Commonly, it includes a package manager, an init system (such as systemd, OpenRC, SysVinit, or runit), GNU tools and libraries, documentation, IP network configuration utilities, the getty TTY setup program, and many more. To provide a desktop experience (most commonly the Mesa userspace graphics drivers) a display server (the most common being the X.org Server, or, more recently, a Wayland compositor such as Sway, KDE's KWin, or GNOME's Mutter), a desktop environment (most commonly GNOME, KDE Plasma, or Xfce), a sound server (usually either PulseAudio or more recently PipeWire), and other related programs may be included or installed by the user.

KDE Plasma is a graphical shell developed by the KDE community for Unix-like operating systems. It serves as the interface layer between the user and the operating system, providing a graphical user interface (GUI) and workspace environment for launching applications, managing windows, and interacting with files and system settings. Plasma is designed to be modular and adaptable, with different variants tailored for specific device types, such as Plasma Desktop for personal computers, and Plasma Mobile for smartphones.

Plasma was first introduced in 2008 as part of KDE Software Compilation 4, as a major technical overhaul, combining traditional desktop functionality with a widget-based system designed for flexibility and visual consistency. With the KDE brand repositioning in 2009, the KDE software compilation was split into three distinct projects: KDE Plasma, KDE Frameworks and KDE Gear, allowing each to develop and release on independent schedules. As of the Plasma 6 series, feature updates are released every four months, with interim bugfix releases.

The KDE Gear is a set of applications and supporting libraries that are developed by the KDE community, primarily used on Linux-based operating systems but mostly multiplatform, and released on a common release schedule.

The bundle is composed of over 200 applications. Examples of prominent applications in the bundle include the file manager Dolphin, document viewer Okular, text editor Kate, archiving tool Ark and terminal emulator Konsole.

The KDE Advanced Text Editor, or Kate, is a source code editor developed by the KDE free software community. It has been a part of KDE Software Compilation since version 2.2, which was first released in 2001. Intended for software developers, it features syntax highlighting, code folding, customizable layouts, multiple cursors and selections, regular expression support, and extensibility via plugins. The text editor's mascot is Kate the Cyber Woodpecker.

KDE e.V. is a non-profit organization that represents the KDE community in legal and financial matters. Founded on 27 November 1997, it is headquartered in Berlin, Germany. The association supports KDE through monetary, hardware, and other donations, which are used to aid development efforts without influencing the direction of the project's development. The abbreviation 'e.V.' stands for eingetragener Verein, meaning 'registered association' in German.

Editing documents, program code, or any data always risks introducing errors. Displaying the differences between two or more sets of data, file comparison tools can make computing simpler, and more efficient by focusing on new data and ignoring what did not change. Generically known as a diff after the Unix diff utility, there are a range of ways to compare data sources and display the results.

Some widely used file comparison programs are diff, cmp, FileMerge, WinMerge, Beyond Compare, and File Compare.

The Start menu (called Start screen in Windows 8, 8.1, Server 2012, and Server 2012 R2) is a graphical user interface element that has been part of Microsoft Windows since Windows 95, providing a means of opening programs and performing other functions in the Windows shell. The Start menu, and the taskbar on which it appears, were created and named in 1993 by Daniel Oran, a program manager at Microsoft who had previously collaborated on great ape language research with the behavioral psychologist B.F. Skinner at Harvard.

The Start menu was renamed Start screen in Windows 8, before returning to its original name with Windows 10. It has been co-opted by some operating systems (like ReactOS) and Linux desktop environments for providing a more Windows-like experience, and as such is, for example, present in KDE, with the name of Kickoff Application Launcher, and on Xfce with the name of Whisker Menu.