Free software in the context of The Free Software Definition

Google Chrome is a cross-platform web browser developed by Google. It was first released in 2008 for Microsoft Windows, built with free software components from Apple WebKit and Mozilla Firefox. Versions were later released for Linux, macOS, iOS, iPadOS, and also for Android, where it is the default browser. The browser is also the main component of ChromeOS, on which it serves as the platform for web applications.

Most of Chrome's source code comes from Google's free and open-source software project known as Chromium, but Chrome is licensed as proprietary freeware. WebKit was the original rendering engine, but Google eventually forked it to create the Blink engine; all Chrome variants except iOS used Blink as of 2017.

LaTeX (/ˈlɑːtɛx/ LAH-tekh or /ˈleɪtɛx/ LAY-tekh, often stylized as LaTeX) is a software system for typesetting documents, based on TeX. LaTeX provides a high-level, descriptive markup language to utilize TeX more easily: TeX handles the document layout, while LaTeX handles the content side for document processing. Because the plain TeX formatting commands are elementary, it provides authors with ready-made commands for formatting and layout requirements such as chapter headings, footnotes, cross-references and bibliographies.

LaTeX was originally written in the early 1980s by Leslie Lamport at SRI International. The current version is LaTeX2e, first released in 1994 but incrementally updated starting in 2015. This update policy replaced earlier plans for a separate release of LaTeX3, which had been in development since 1989. LaTeX is free software and is distributed under the LaTeX Project Public License (LPPL).

Qt Extended (named Qtopia before September 30, 2008) is an application platform for embedded Linux-based mobile computing devices such as personal digital assistants, video projectors and mobile phones. It was initially developed by The Qt Company, at the time known as Qt Software and a subsidiary of Nokia. When they cancelled the project the free software portion of it was forked by the community and given the name Qt Extended Improved. The QtMoko Debian-based distribution is the natural successor to these projects as continued by the efforts of the Openmoko community.

Free and open-source software (FOSS) is software available under a license that gives users the right to use, share, modify, and distribute the software – modified or not – to everyone and provides the means to exercise those rights using the software's source code. FOSS is an inclusive umbrella term encompassing free software and open-source software. The rights guaranteed by FOSS originate from the "Four Essential Freedoms" of The Free Software Definition and the criteria of The Open Source Definition. All FOSS can have publicly available source code, but not all source-available software is FOSS. FOSS is the opposite of proprietary software, which is licensed restrictively or has undisclosed source code.

The historical precursor to FOSS was the hobbyist and academic public domain software ecosystem of the 1960s to 1980s. Free and open-source operating systems such as Linux distributions and descendants of BSD are widely used, powering millions of servers, desktops, smartphones, and other devices. Free-software licenses and open-source licenses have been adopted by many software packages. Reasons for using FOSS include decreased software costs, increased security against malware, stability, privacy, opportunities for educational usage, and giving users more control over their own hardware.

An open file format is a file format for storing digital data, defined by an openly published specification usually maintained by a standards organization, and which can be used and implemented by anyone. An open file format is licensed with an open license.For example, an open format can be implemented by both proprietary and free and open-source software, using the typical software licenses used by each. In contrast to open file formats, closed file formats are considered trade secrets.

Depending on the definition, the specification of an open format may require a fee to access or, very rarely, contain other restrictions. The range of meanings is similar to that of the term open standard.

CompCert is a formally verified optimizing compiler for a large subset of the C99 programming language (known as Clight) which currently targets PowerPC, ARM, RISC-V, x86 and x86-64 architectures. This project, led by Xavier Leroy, started officially in 2005, funded by the French institutes ANR and INRIA. The compiler is specified, programmed and proven in the Rocq proof assistant. It aims to be used for programming embedded systems requiring reliability. The performance of its generated code is often close to that of GCC (version 3) at optimization level -O1, and always better than that of GCC without optimizations.

Since 2015, AbsInt offers commercial licenses, provides support and maintenance, and contributes to the advancement of the tool. CompCert is released under a noncommercial license, and is therefore not free software, although some of its source files are dual-licensed with the GNU Lesser General Public License version 2.1 or later or are available under the terms of other licenses.

Horde is a free web-based groupware. The components of this groupware rest on the Horde framework, a PHP-based framework provides all the elements required for rapid web application development. Horde offers applications such as the Horde IMP email client, a groupware package (calendar, notes, tasks, file manager), a wiki and a time and task tracking software.

FUDforum is a free and open-source Internet forum software, originally produced by Advanced Internet Designs Inc., that is now maintained by the user community. The name "FUDforum" is an abbreviation of Fast Uncompromising Discussion forum. It is comparable to other forum software. FUDforum is customizable and has a large feature set relative to other forum packages.

FUDforum runs on a number of operating systems that are able to support the PHP programming language, including Unix, Linux and Windows systems. The interface is based on HTML5 with CSS, jQuery and AJAX.

Mozilla is a free software community founded in 1998 by members of Netscape. The Mozilla community uses, develops, publishes, and supports Mozilla products, thereby promoting free software and open standards. The community is supported institutionally by the non-profit Mozilla Foundation and its tax-paying subsidiary, the Mozilla Corporation.

Mozilla's current products include the Firefox web browser, Thunderbird e-mail client (now through a subsidiary), the Bugzilla bug tracking system, and the Gecko layout engine.

FreeBSD is a free-software Unix-like operating system descended from the Berkeley Software Distribution (BSD). The first version was released in 1993 developed from 386BSD, one of the first fully functional and free Unix clones on affordable home-class hardware, and has since continuously been the most commonly used BSD-derived operating system.

FreeBSD maintains a complete system, delivering a kernel, device drivers, userland utilities, and documentation, as opposed to Linux only delivering a kernel and drivers, and relying on third-parties such as GNU for system software. The FreeBSD source code is generally released under a permissive BSD license, as opposed to the copyleft GPL used by Linux. The project includes a security team overseeing all software shipped in the base distribution. Third-party applications may be installed using the pkg package management system or from source via FreeBSD Ports. The project is supported and promoted by the FreeBSD Foundation.

OpenBSD is a security-focused, free software, Unix-like operating system based on the Berkeley Software Distribution (BSD). Theo de Raadt created OpenBSD in 1995 by forking NetBSD 1.0. The OpenBSD project emphasizes portability, standardization, correctness, proactive security, and integrated cryptography.

The OpenBSD project maintains portable versions of many subsystems as packages for other operating systems. Because of the project's preferred BSD license, which allows binary redistributions without the source code, many components are reused in proprietary and corporate-sponsored software projects. The firewall code in Apple's macOS is based on OpenBSD's PF firewall code, Android's Bionic C standard library is based on OpenBSD code, LLVM uses OpenBSD's regular expression library, and Windows 10 uses OpenSSH (OpenBSD Secure Shell) with LibreSSL.

Hyphanet (until mid-2023: Freenet) is a peer-to-peer platform for censorship-resistant, anonymous communication. It uses a decentralized distributed data store to keep and deliver information, and has a suite of free software for publishing and communicating on the Web without fear of censorship. Both Freenet and some of its associated tools were originally designed by Ian Clarke, who defined Freenet's goal as providing freedom of speech on the Internet with strong anonymity protection.

The distributed data store of Freenet is used by many third-party programs and plugins to provide microblogging and media sharing, anonymous and decentralised version tracking, blogging, a generic web of trust for decentralized spam resistance, Shoeshop for using Freenet over sneakernet, and many more.

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.

The adjective free in English is commonly used in one of two meanings: "at no monetary cost" (gratis) or "with little or no restriction" (libre). This ambiguity can cause issues where the distinction is important, as it often is when dealing with laws concerning the use of information, such as copyright and patents.

The terms gratis and libre may be used to categorise intellectual property like computer programs, according to the licenses and legal restrictions that cover them, especially in the free software and open source communities, as well as the broader free culture movement. For example, they are used to distinguish "freeware" (software gratis) from free software (software libre).

The Linux kernel is a free and open-source Unix-like kernel that is used in many computer systems worldwide. The kernel was created by Linus Torvalds in 1991 and was soon adopted as the kernel for the GNU operating system (OS) which was created to be a free replacement for Unix. Since the late 1990s, it has been included in many operating system distributions, many of which are called Linux. One such Linux kernel operating system is Android which is used in many mobile and embedded devices.

Most of the kernel code is written in C as supported by the GNU Compiler Collection (GCC) which has extensions beyond standard C. The code also contains assembly code for architecture-specific logic such as optimizing memory use and task execution. The kernel has a modular design such that modules can be integrated as software components – including dynamically loaded. The kernel is monolithic in an architectural sense since the entire OS kernel runs in kernel space.

FLAC (/flæk/; Free Lossless Audio Codec) is an audio coding format for lossless compression of digital audio, developed by the Xiph.Org Foundation, and is also the name of the free software project producing the FLAC tools, the reference software package that includes a codec implementation. Digital audio compressed by FLAC's algorithm can typically be reduced to between 50 and 70 percent of its original size and decompresses to an identical copy of the original audio data.

FLAC is an open format with royalty-free licensing and a reference implementation which is free software. FLAC supports metadata tagging, album cover art, and fast seeking.

The LaTeX Project Public License (LPPL) is a software license originally written for the LaTeX system. Software distributed under the terms of the LPPL can be regarded as free software; however, it is not copylefted.

Besides the LaTeX base system, the LPPL is also used for most third-party LaTeX packages. Software projects other than LaTeX rarely use it.

A software license is a legal instrument governing the use or redistribution of software.

Since the 1970s, software copyright has been recognized in the United States. Despite the copyright being recognized, most companies prefer to sell licenses rather than copies of the software because it enables them to enforce stricter terms on redistribution. Very few purchasers read any part of the license, initially shrink-wrap contracts and now most commonly encountered as clickwrap or browsewrap. The enforceability of this kind of license is a matter of controversy and is limited in some jurisdictions. Service-level agreements are another type of software license where the vendor agrees to provide a level of service to the purchaser, often backed by financial penalties.