[scofalik]

The idea behind storing and loading the data is, in short, this: HTML is the most popular format and it is the default when it comes to publishing web content. Most people want HTML data.

However, it is understood that in the modern web era, there is a need for more. In CKE5 there is a "data processor" unit. The data processor is responsible for taking DOM (generated from editor's data model) and converting it to the output you want. The default processor is HTML processor, but you could hook there any processor that can convert DOM structure to anything you want. You can use already existing libraries or write your own if you need something really custom.

To sum up, the road from editor's model to the output data is this: custom model -> view (DOM-like structure) -> DOM -> Data processor -> stringified data