Amazon Device Messaging (ADM) support for Fire Web

I am looking for a working solution, to use the Amazon Device Messaging (ADM) API in HTML5/Web Apps for Amazon Kindle (Fire OS), especially for packaged apps.

There is no reference in the Fire Web HTML5 matrix.

firefox and chrome can handle push notifications, by using the Simple Push API and/or Google Cloud Messaging API.

However, the documentation mentions an Amazon Web App API:

Packaged Apps

For packaged apps, the Amazon API JavaScript file is automatically injected at the root level of your .zip file. Use a relative URL in your tag to refer to that file.

From within index.html: <script src="Amazon-Web-App-API.min.js"></script>

Unfortunately, this API seems to be undocumented.

What are the capabilities of the Amazon Web App API ?