Add Data Widget in Portal - What Geocoder Does It Use?

[AmyRoust]

I've got the Add Data widget added to a WAB Developer Edition web app. If you drag and drop a CSV with XY data in it, the widget performs properly. If the CSV file only has addresses, it does not work. According to CSV, TXT, and GPX files—ArcGIS Online Help | Documentation, CSVs with fields called Address, City, State, and Zip should work.

I've checked in my Portal settings (using 10.7.1) and I've got the ArcGIS World Geocoding Service set as my first Geocoder under Utility Services.

Does anyone know what geocoder the widget is supposed to use? There isn't any place in the Add Data configuration to define a URL.