Selected Part:
First Node's data:
Model.modelData:

An HTML-based inspector that displays and allows editing of data for the selected Part (if any), or for a particular JavaScript object, or for the shared Model.modelData object, which exists even if there are no nodes or links.

The inspector code lies in DataInspector.js and DataInspector.css. This code is meant to be a starting point for making your own model data inspector.

On browsers that support it, color types display a color picker. There are various plugins and polyfills for this functionaltiy if you wish to extend the data inspector.

This shows the contents of the model after each transaction: