The various options that you can see in the menu are the result of performing the same bussiness logic functions, but implemented in different languages. All the bussiness logic functions return the same XML, except one attribute called Impl that returns the implementation language so you can see they are indeed different. The XML is always processed through the same Freemarker template, so it generates always the same HTML.
The first option is the XML prototype processed with Freemarker, and that is what one can do when no bussiness logic has been implemented yet, so you can start working on the Freemarker template even before any code has been written. The other options are real implementations in code and you can modify the data through the simple form that is created. Be aware that some versions, JavaScript & Jython, have just the "listing" functionality implemented, so you cannot modify the data with them.
This demonstrates the flexibility of an MVC architecture, WebLEAF in this case, where you can implement the bussiness logic through very different ways, and the presentation logic is completely independent.
You can can see the sources of the various files that are used in this section, at the Fisheye repository: