I create a lot of demo content which always need corresponding documentation. I'm a big fan of keeping both the demo and the documentation together, since one or the other will inevitably become lost and/or separated. As part of this effort, I wanted a way to display the demo within the documentation in manner that was useful. As an example, you can load this paragraph into the viewer, or even load predefined templates.
You can load more complicated content into it, such as this card.