Not sure if this is the right place for this post but it is related to the training documentation. I noticed the below text in the documentation for the T3 test under Templates and Rendering and as far as I know only the Template Extenders are used to extend what is output to the page. Is there something that I am missing here? What methods can be extended using the notification subscribers ?
All sections (app, paragraph, and page) have an output method which outputs the content as a string value. These methods may be extended using notification subscribers, which makes it possible to manipulate the content/output.