UseQApplication: use QApplication over QGuiApplication (for qqc2-desktop-style)
NativeTextRendering: use NativeTextRendering over QtRendering for text
Env VAR = VAL: define environment variables (usually qt ones)
A fair amount of things are broken but not in the layershell interface
itself. The shell window platform extensions are next in line for
refactoring and relevent issues will be fixed then. Same for docs.