KDE Free Qt Foundation

The KDE Free Qt Foundation is a Norwegian foundation (stiftelse) whose stated purpose is to secure the availability of the Qt toolkit for the development of Free Software and, in particular, for the development of KDE software. It was constituted in 1998, at a time when Qt was still a proprietary product of the company Trolltech. The Foundation operates through license agreements with the commercial holders of Qt — historically Trolltech, later Nokia and Digia, and today Qt Group — which oblige those companies to keep a Free Edition of Qt available under the required open-source licenses. The Foundation's central mechanism is a fallback right: should Qt Group discontinue development of the Qt Free Edition under the required licenses, the Foundation has the right to release Qt under a BSD-style license or under other open-source licenses. The agreements are designed to survive a buy-out, a merger or a bankruptcy, so that the open-source availability of Qt cannot be extinguished by a change of corporate control. The most recent agreement covers all releases of all Qt versions on a set of core platforms — X11 (desktop Linux) and Android, where support cannot be dropped — and additional platforms including Microsoft Windows, Windows Phone, Apple macOS and Apple iOS, for as long as Qt Group supports them at all. The Foundation may update to supported successor platforms, for example from X11 to Wayland, without additional negotiations with Qt Group. The required license terms are specific: all parts of Qt must be available under GPLv3 or a compatible license; most parts are also available under LGPLv3 and GPLv2; the core libraries of Qt (Essentials) and all existing LGPL-licensed Qt add-ons must continue to be available under LGPLv3; GPLv2-compatibility must be kept for all existing GPLv2-licensed Qt code, for the core part of Qt (Essentials) and for the Qt applications; future versions of the GPL are supported if approved by the KDE Free Qt Foundation; and applications included in Qt, such as Qt Creator, must be licensed under GPLv2 and GPLv3. The Foundation is closely associated with the KDE Community and is documented on KDE's own website. It is not a commercial vendor: it does not sell Qt, but acts as a legal guarantor of Qt's open-source licensing. Its counterparties are the commercial Qt companies, and its beneficiaries are KDE and the broader Free Software ecosystem that depends on Qt.

The KDE Free Qt Foundation was constituted in 1998, at a time when the Qt toolkit was a proprietary product of the Norwegian company Trolltech. Its founding purpose was to guarantee a free and open version of the Qt libraries and, by extension, the development of KDE as Free Software. KDE, the desktop environment and community, was built on Qt, so the licensing status of Qt was an existential question for the project. On 18 July 2004, Trolltech and the Foundation agreed to secure the development of the libraries independently of Trolltech — whether Trolltech abandoned them or was acquired by another company. In either case, Qt would be released under a BSD or similar license. This agreement established the fallback mechanism that remains the Foundation's core instrument. Over time the commercial counterparty to the Foundation changed as Qt changed hands. The Foundation has had license agreements with Trolltech, later with Nokia, then with Digia, and today with Qt Group. Each successive agreement has preserved the Foundation's right to release Qt under a BSD-style license or other open-source licenses if the Qt Free Edition is discontinued under the required licenses, and the agreements are structured to remain valid in the event of a buy-out, a merger or a bankruptcy. The most recent agreement broadens and modernizes the platform coverage. It covers all releases of all Qt versions on core platforms — X11 (desktop Linux) and Android — where support cannot be dropped, and on additional platforms including Microsoft Windows, Windows Phone, Apple macOS and Apple iOS for as long as Qt Group supports them. The Foundation may move to supported successor platforms, such as Wayland in place of X11, without renegotiating with Qt Group. The agreement also specifies the license terms that must be maintained: all parts of Qt under GPLv3 or a compatible license; most parts also under LGPLv3 and GPLv2; the core libraries of Qt (Essentials) and all existing LGPL-licensed Qt add-ons under LGPLv3; GPLv2-compatibility for all existing GPLv2-licensed Qt code, for the core part of Qt (Essentials) and for the Qt applications; future GPL versions if approved by the Foundation; and applications included in Qt, such as Qt Creator, under GPLv2 and GPLv3. Through these agreements the Foundation has functioned for decades as a stable, non-commercial guarantor of Qt's open-source availability, protecting KDE and the wider Free Software ecosystem from the risk that a change in Qt's ownership or strategy could close the toolkit.

• 2004

  On 18 July 2004, Trolltech and the Foundation agree to secure the development of the libraries independently of Trolltech, with Qt to be released under a BSD or similar license if abandoned or if Trolltech is acquired.

• 1998

  The KDE Free Qt Foundation is constituted to guarantee a free version of the Qt libraries and the development of KDE as Free Software.

• License agreements are concluded successively with Trolltech, Nokia, Digia and Qt Group, preserving the Foundation's fallback right to release Qt under a BSD-style or other open-source license.

• The most recent agreement covers all releases of all Qt versions on core platforms (X11 and Android) and additional platforms (Windows, Windows Phone, macOS, iOS), and specifies the required GPLv3/LGPLv3/GPLv2 license terms.

A non-commercial legal guarantor of Qt's open-source licensing, acting through binding agreements with Qt's commercial owners.

1. 1KDE Free Qt Foundation - KDE Communitykde.org
2. 2KDE Free Qt Foundation (Wikidata)wikidata.org
3. 3KDE Free Qt Foundation (Wikipedia en español)es.wikipedia.org