Qt is a software development framework with ready-made libaries and tools. Value of Qt is the speed and ease of development regardless of underlying platform.
Qt is dual-licensed under either commercial or open source licenses. Qt is developed by the Qt project with open governance model. The biggest contributor and IPR owner of the Qt is The Qt Company.
In order to develop and distribute your product with Qt, you must adhere to obligations and definitions enforced by either the commercial or the open source licensing.