Dozuki - Dozuki is a web-based tool for creating and distributing step-by-step documentation.
wxWidgets - wxWidgets: Cross-Platform GUI Library
ClassVR - VR Training Simulator
Electron - Build cross platform desktop apps with web technologies
ScreenSteps - IT Training Docs For Your Cloud Implementation. Use ScreenSteps when your company implements new cloud technology and you need training docs
GTK - GTK+ is a multi-platform toolkit for creating graphical user interfaces.