MuseScore is a scorewriter for Windows, macOS, and Linux, comparable to Finale and Sibelius, supporting a wide variety of file formats and input methods. It is released as free and open-source software under the GNU General Public License. MuseScore is accompanied by a freemium mobile score viewer and playback app, and an online score sharing platform.
UReadIt is a simple browser for reddit.com on Ubuntu phones. It utilizes the Reddit API, to read and post articles and coments, inbox management, and up/downvoting. It uses QML and also works in Desktop view.
Plasma is the desktop component of KDE. It's shell is modularly designed and can harbour nested applets and widgets besides traditional icon shortcuts. It's based entirely on Qt5 with QML (Qt modeling language), KDE Frameworks 5, and OpenGL rendering.