The Qube UI plugin system uses the Python 3 language to define new menus, panels, and submission interfaces. Custom themes are written in a modified QSS format. Internally, the Qube! UI uses PythonQt to interface with Python 3, this is exposed to the Python 3 based plugins, the entire suite of Qt is available.
Plugin files are generally found inside the Qube! UI application directory (or QubeUI\bin on Windows) but you can also add your own paths in the UI preferences.
Beneath each plugin directory there is a hierarchy of folders that define the plugin type and menu structure (where applicable). For example the following directory structure: