QPE is developed with Qt 5.15.2 and uses at least the Core, GUI, Widgets and OpenGL modules. Qt is not owned by Officina Turini and remains governed by the license under which a user or distributor obtained Qt.
Anyone building or redistributing QPE must verify the terms applicable to the Qt distribution actually used. In particular, using Qt under open-source licensing can impose specific obligations regarding notices, license texts, relinking/replacement of libraries and availability of library source as required by the applicable license.
Official Qt references: Qt Licensing · GPL/LGPL obligations.
The reference Windows build uses Visual Studio 2019/MSVC. Microsoft compiler, SDK and runtime components are governed by Microsoft terms; a binary distributor must verify redistribution rights for the runtime files actually included.
QPE uses OpenGL through Qt. GPU drivers and operating-system graphics components belong to their respective vendors.
Papers, books, DOIs, author names and references cited in the Help remain subject to the rights of their authors and publishers. Citation does not incorporate or relicense the underlying publications.
Any future third-party library, data set, font, image or code added to a QPE package must be accompanied by the notices and license texts required by its terms before release.