I have not released the source of the html render engine (kerbynet). I am thinking if I’ll release it as GPL or not. Probably, next release will include the license of kerbynet that in any case will be free when distributed with Zeroshell.
It is already possible to implement new feature without changing kerbynet by using the Action=Object in the URL and executing the scripts with the tag with root privileges and with not root privileges. I’m working to produce some documentation to make this easier.