data-emptytext AEM logic

Does anyone know where to find any documentation of how the data-emptytext <div> tag attribute works in detail ? What tells whether some content has been added to a component or not to display data-emptytext value as a text message?

I've tried to Google for it, but no info available. Even docs.adobe.com has nothing.

The problem is that data-emptytext="Some Component Name" does not work on my component that generates a simple HTML code when some data has been entered (via Edit Dialog). How does the system understand that some data has been populated to the component to not show the "emptytext" value ?

Example of the first component renderer string:

<div data-sly-test.author="${wcmmode.edit || wcmmode.design}" class="cq-placeholder section" data-emptytext="Some Component Name"></div>