On the relationship between Qt and KDE
Volker Hilsheimer, chief maintainer of the Qt project, says he has learned lessons from the painful Qt 5 to Qt 6 transition, the importance of Qt Bridges for using Qt from any language, and the significance of the relationship with the Linux KDE desktop.
↫ Tim Anderson at Dev Class
Qt plays a significant role in the open source desktop world in particular, because it’s the framework KDE uses. Hilsheimer notes that KDE’s role in the Qt community is actually quite important, because not only is it a source of people learning how to use Qt and who can thus make contributions to the project, KDE also tends to use the latest Qt versions, creating a lot of confidence among the wider Qt community to also adopt the latest versions.
The relationship with KDE and Qt is an interesting one, and sometimes leads to questions about the future availability of the open source edition of Qt since the Qt Company licenses Qt under a dual-license structure (both open and proprietary). To avoid any uncertainty, KDE and Qt have an agreement that covers pretty much every possible scenario and which is worded to ensure the availability of Qt as an open source framework.
KDE, through the KDE Free Qt Foundation, has a number rights and options to ensure the availability of Qt as an open source framework. I’m no lawyer, so I might get some of the details wrong, but the main points are that if the Qt Company ever decides to discontinue the open source edition of Qt, the KDE Free Qt Foundation has the right to release Qt under a BSD-style license within 12 months. The same applies to any addition to Qt which are not released as open source; they must be released under an open source license within 12 months of initial release. This agreement remains valid in the case of buyouts, mergers, or bankruptcies.
This agreement has existed in one form or another since the late ’90s, and has survived Qt being owned by Nokia and Digia, as well as various other organisational changes. Despite the issue of Qt’s ownership coming up every now and then, the agreement is pretty airtight, and considering its longevity there’s no reason to be worried about it at all.
Still, this structure is clearly more complex and less straightforward than, say, the status of GTK and its relationship to GNOME, so it’s not entirely unreasonable the issue comes up every now and then. I wonder if we’ll ever see this situation become less complex, without the need for special agreements. While it wouldn’t make a practical difference, it would make things less… Legalese.