MIT Punya is an extension of the MIT App Inventor platform aimed at more advanced uses. We sometimes use it to test out more advanced features before adapting them to use in MIT App Inventor. For example, it added Google Maps before we eventually developed the Map components for App Inventor, and it previewed the Chart component before its official release. I've been working on an update to Punya and there is now a new test companion if you are interested in trying it.