Firstly. We are not relying on JavaScript to do most of the work. We have a backend (PHP), to do server side functions, and then the front-end (JavaScript) to do client side functions.
The compartmentalisation is sound. Since it’s using the backend as an API it would be possible to write a CLI client for it. Heck. Write an iPhone app. All it has to do is call the PHP script with a get request.
Secondly, @_k_h is 100% correct. It’s a shell xD therefore you aren’t going to gain much by hacking it. In fact. You won’t gain anything. If you could hack it for more functionality we would actually impliment those features into the shell 