Single Submission Surveys via Enketo

The Enketo blog [] introduces this new feature.
Here is a screen grab -

How to Use

No need to add anything to your XLSForm. You have the following options to use this feature for any form:

A. Be an activist

You could actively request any Enketo-powered service to leverage this new feature. Those services rely on your feedback to continuously improve.

B. Use your own Enketo Express installation

Make sure to populate the new config.json item and use this API endpoint to request a webform URL.

How would I go about getting this activated on KoboToolBox using option A above?