GNU General Public License in the context of MySQL

Open-source licenses are software licenses that allow content to be used, modified, and shared. They facilitate free and open-source software (FOSS) development. Intellectual property (IP) laws restrict the modification and sharing of creative works. Free and open-source licenses use these existing legal structures for an inverse purpose. They grant the recipient the rights to use the software, examine the source code, modify it, and distribute the modifications. These criteria are outlined in the Open Source Definition.

After 1980, the United States began to treat software as a literary work covered by copyright law. Richard Stallman founded the free software movement in response to the rise of proprietary software. The term "open source" was used by the Open Source Initiative (OSI), founded by free-software developers Bruce Perens and Eric S. Raymond. "Open source" emphasizes the strengths of the open development model rather than software freedoms. While the goals behind the terms are different, open-source licenses and free-software licenses describe the same type of licenses.

Freeciv is a single- and multiplayer turn-based strategy game for workstations and personal computers inspired by the proprietary Sid Meier's Civilization series. It is available for most desktop computer operating systems and available in an online browser version. Released under the GNU GPL-2.0-or-later, Freeciv is free and open-source software. The game's default settings are closest to Civilization II, in both gameplay and graphics, including the units and the isometric grid. However, with a lot of multiplayer games being played in longturn communities, rulesets and additional variants have evolved away from the original ruleset. Freeciv is playable online on various public and private servers.

Players take the role of tribal leaders in 4000 B.C. who must guide their peoples through the centuries. Over time, new technologies are discovered, which allow the construction of new city buildings and the deployment of new units. Players can wage war on one another or form diplomatic relationships.

phpBB is an Internet forum package written in the PHP scripting language. The name "phpBB" is an abbreviation of PHP Bulletin Board. Available under the GNU General Public License, phpBB is free and open-source.

Features of phpBB include support for multiple database engines (MariaDB, Microsoft SQL Server, MySQL, PostgreSQL, SQLite, Oracle Database), flat message structure (as opposed to threaded), hierarchical subforums, topic split/merge/lock, user groups, multiple attachments per post, full-text search, plugins and various notification options (e-mail, Jabber instant messaging, ATOM feeds).

NonVisual Desktop Access (NVDA) is a free and open-source, portable screen reader for Microsoft Windows. The project was started by Michael Curran in 2006.

NVDA is programmed in Python. It utilizes accessibility APIs such as UI Automation, Microsoft Active Accessibility, IAccessible2 and Java Access Bridge, to access and present information to the user. It is licensed under the GNU General Public License version 2.

ArduPilot is an autopilot software program that can control multirotor drones, fixed-wing and VTOL aircraft, RC helicopters, ROVs, ground rovers, boats, submarines, uncrewed surface vessels (USVs), AntennaTrackers and blimps. It is published as open source software under the GNU GPL version 3.

ArduPilot was originally developed by hobbyists to control model aircraft and rovers and has evolved into a full-featured and reliable autopilot used by industry, research organisations, amateurs, and militaries. In June 2025 ArduPilot was used successfully by the Ukrainian armed forces during the Russo-Ukrainian War to make aerial drone attacks on Russian air bases.

The Free Software Foundation (FSF) is a 501(c)(3) non-profit organization founded by Richard Stallman on October 4, 1985. The organization supports the free software movement, with its preference for software being distributed under copyleft ("share alike") terms, such as with its own GNU General Public License. The FSF was incorporated in Boston where it is also based.

From its founding until the mid-1990s, FSF's funds were mostly used to employ software developers to write free software for the GNU Project and its employees and volunteers have mostly worked on legal and structural issues for the free software movement and the free software community. Consistent with its goals, the FSF aims to use only free software on its own computers.

Arduino (/ɑːrˈdwiːnoʊ/) is an Italian open-source hardware and software company owned by Qualcomm, project, and user community that designs and manufactures single-board microcontrollers and microcontroller kits for building digital devices. Its hardware products are licensed under a CC BY-SA license, while the software is licensed under the GNU Lesser General Public License (LGPL) or the GNU General Public License (GPL), permitting the manufacture of Arduino boards and software distribution by anyone. Arduino boards are available commercially from the official website or through authorized distributors.

Arduino board designs use a variety of microprocessors and controllers. The boards are equipped with sets of digital and analog input/output (I/O) pins that may be interfaced to various expansion boards ('shields') or breadboards (for prototyping) and other circuits. The boards feature serial communications interfaces, including Universal Serial Bus (USB) on some models, which are also used for loading programs. The microcontrollers can be programmed using the C and C++ programming languages (Embedded C), using a standard API which is also known as the Arduino Programming Language, inspired by the Processing language and used with a modified version of the Processing IDE. In addition to using traditional compiler toolchains, the Arduino project provides an integrated development environment (IDE) and a command line tool developed in Go.

The GNU Lesser General Public License (LGPL) is a free-software license published by the Free Software Foundation (FSF). The license allows developers and companies to use and integrate a software component released under the LGPL into their own (even proprietary) software without being required by the terms of a strong copyleft license to release the source code of their own components. However, any developer who modifies an LGPL-covered component is required to make their modified version available under the same LGPL license. For proprietary software, code under the LGPL is usually used in the form of a shared library, so that there is a clear separation between the proprietary and LGPL components. The LGPL is primarily used for software libraries, although it is also used by some stand-alone applications.

The LGPL was developed as a compromise between the strong copyleft of the GNU General Public License (GPL) and more permissive licenses such as the BSD licenses and the MIT License. The word "Lesser" in the title shows that the LGPL does not guarantee the end user's complete freedom in the use of software; it only guarantees the freedom of modification for components licensed under the LGPL, but not for any proprietary components.

The Mozilla Public License (MPL) is a free and open-source weak copyleft license for most Mozilla Foundation software such as Firefox and Thunderbird. The MPL is developed and maintained by Mozilla, which seeks to balance the concerns of both open-source and proprietary developers. It is distinguished from others as a middle ground between the permissive software BSD-style licenses and the GNU General Public License. As such, it allows the integration of MPL-licensed code into proprietary codebases, as long as the MPL-licensed components remain accessible under the terms of the MPL.

MPL has been used by others, such as Adobe to license their Flex product line, and The Document Foundation to license LibreOffice 4.0 (also on LGPL 3+). Version 1.1 was adapted by several projects to form derivative licenses like Sun Microsystems' Common Development and Distribution License. It has undergone two revisions: the minor update 1.1, and a major update version 2.0 nearing the goals of greater simplicity and better compatibility with other licenses.

Richard Matthew Stallman (/ˈstɔːlmən/ STAWL-mən; born March 16, 1953), also known by his initials, rms, is an American free software movement activist and programmer. He campaigns for software to be distributed in such a manner that its users have the freedom to use, study, distribute, and modify that software. Software which ensures these freedoms is termed free software. Stallman launched the GNU Project, founded the Free Software Foundation (FSF) in October 1985, developed the GNU Compiler Collection and GNU Emacs, and wrote all versions of the GNU General Public License.

Stallman launched the GNU Project in September 1983 to write a Unix-like computer operating system composed entirely of free software. With that he also launched the free software movement. He has been the GNU project's lead architect and organizer, and developed a number of pieces of widely used GNU software including among others, the GNU Compiler Collection, GNU Debugger, and GNU Emacs text editor.

GNU (/ɡnuː/ GNOO) is an extensive collection of free software (387 packages as of June 2025), which can be used as an operating system or can be used in parts with other operating systems. The use of the completed GNU tools led to the family of operating systems popularly known as Linux. Most of GNU is licensed under the GNU Project's own General Public License (GPL).

GNU is also the project within which the free software concept originated. Richard Stallman, the founder of the project, views GNU as a "technical means to a social end". Relatedly, Lawrence Lessig states in his introduction to the second edition of Stallman's book Free Software, Free Society that in it Stallman has written about "the social aspects of software and how Free Software can create community and social justice".

GNU Midnight Commander (also known as mc, the command used to start it, and as mouseless commander in older versions) is a free cross-platform orthodox file manager. It was started by Miguel de Icaza in 1994 as a clone of the then-popular Norton Commander.

GNU Midnight Commander is part of the GNU project and is licensed under the terms of the GNU General Public License.

Darktable (stylized as darktable) is a free and open-source photography application and raw developer. Rather than being a raster graphics editor like Adobe Photoshop or GIMP, it comprises a subset of image editing operations specifically aimed at non-destructive raw image post-production. It is primarily focused on improving a photographer's workflow by facilitating the handling of large numbers of images. It is freely available in versions tailored for most major Linux distributions, macOS, Solaris and Windows and is released under the GPL-3.0-or-later software license.

Qt (/ˈkjuːt/ pronounced "cute") is a cross-platform application development framework for creating graphical user interfaces as well as cross-platform applications that run on various software and hardware platforms such as Linux, Windows, macOS, Android or embedded systems with little or no change in the underlying codebase while still being a native application with native capabilities and speed.

Qt is currently being developed by The Qt Company, a publicly listed company, and the Qt Project under open-source governance, involving individual developers and organizations working to advance Qt. Qt is available under both commercial licenses and open-source GPL 2.0, GPL 3.0, and LGPL 3.0 licenses.

The GNU Compiler Collection (GCC) (formerly GNU C Compiler) is a collection of compilers from the GNU Project that support various programming languages, hardware architectures, and operating systems. The Free Software Foundation (FSF) distributes GCC as free software under the GNU General Public License (GNU GPL). GCC is a key component of the GNU toolchain which is used for most projects related to GNU and the Linux kernel. With roughly 15 million lines of code in 2019, GCC is one of the largest free programs in existence. It has played an important role in the growth of free software, as both a tool and an example.

When it was first released in 1987 by Richard Stallman, GCC 1.0 was named the GNU C Compiler since it only handled the C programming language. It was extended to compile C++ in December of that year. Front ends were later developed for Objective-C, Objective-C++, Fortran, Ada, Go, D, Modula-2, Rust and COBOL among others. The OpenMP and OpenACC specifications are also supported in the C and C++ compilers.