The demo is published on this page.
It just shows a gauge control displayed with one of its skins called 'Modern'. Here is the source code.
(in addition to those already explained in the previous demo)
The gauge control was actually already implemented in a JavaFX called Medusa. This is an example of how you can benefit from the JavaFX ecosystem and reuse or port existing JavaFX libraries in your WebFX applications.
This demo also shows that it's possible to write your own control with the JavaFX API and implement one or even several skins for the same control.