When loading the package in the modeler:
Client module specifies file path 'BootstrapRTE/widget/' that does not exist in the package.
Note: seems to have something to do with the spaces/returns in the package.xml file. When comparing the file to the 3.x versions there are some extra. After removing them, the widget loads in the modeler but when starting the app it returns "No constructor found for widget BootstrapRTE.widget.BootstrapRTE" when showing a page.