No, the main GUI is QT, it's for a user plugin system called 'Workflow Integration Plugins'.
The docs about this are not on the web so I can't link to it, but you can access them in the App's help menu.
Quote from those docs:
> Users can write their own Workflow Integration Plugin (an Electron app), using Resolve Javascript’s
API, and Python or Lua scripts. For more information on how to create a Workflow Integration Plugin
go to Help > Documentation > Developer, and open up the Workflow Integrations folder for technical
details and sample code.
The docs about this are not on the web so I can't link to it, but you can access them in the App's help menu.
Quote from those docs:
> Users can write their own Workflow Integration Plugin (an Electron app), using Resolve Javascript’s API, and Python or Lua scripts. For more information on how to create a Workflow Integration Plugin go to Help > Documentation > Developer, and open up the Workflow Integrations folder for technical details and sample code.