in hise 1.1 when you make the interface graphically the on init script reflect the additions in code this process don't happens in hise 2.0
In HISE 2 all of the JSON code is hidden. You should build your interface using the interface designer rather than doing it through scripting, except in some specific instances. In the interface designer you can click on one of your widgets and press the j on your keyboard to see the JSON code.
When you save your project as an XML file all of the UI data is saved too in a separate XML file in a sub-folder in the XMLPresetBackups folder.