3.2. Why do you have an agreement with KDE about your licensing? What KDE is and what’s the history of Qt and KDE?

KDE is an international free software community, founded in 1996, producing an integrated set of cross-platform applications for desktop and mainly known for its Plasma Desktop environment, which is provided as the default work environment on many Linux distributions. KDE software is based on the Qt framework. In the early days of Qt, the KDE project and community was the biggest driving force in building the developer ecosystem around Qt.

In the very early days, Qt was already dual-licensed, but the source code was available under proprietary open source licenses. Compromises with KDE were sought to ensure that Qt would be available for their use under appropriate open source licensing even if Trolltech (the company that founded Qt) would be bought or go bankrupt. As a result, The KDE Free Qt Foundation was founded.

The KDE Free Qt Foundation is an organization with the purpose of securing the availability of the Qt toolkit for the development of Free Software and in particular for the development of KDE software. The Foundation was originally founded by Trolltech and the KDE e.V. (the legal non-profit organization behind KDE) in 1998 and it has a license agreement that ensures the availability of Qt under LGPLv3 and GPLv3 licenses for major desktop and mobile platforms. The license agreement has been updated couple of times over the years, mainly because of acquisitions around Qt or updates to licenses and platforms.