This particular content pane invokes the loading of dijit/dijit-all via declarative markup. This is intended to simulate that invoking of loading an application layer from a custom build. Once your application layer is loaded, if your module is included in that, then it will not be loaded again.
This means that you can load application layers declaratively and only when first needed by including them in your declaritive markup.
The way this is accomplish is that the parser now supports the ability to run the require(); command in declarative markup without instantiating an object by using the data-dojo-command attribute like this:
<div data-dojo-command="require" data-dojo-args="dijit/dijit-all"></div>