Is there a resources where I can find all the $ variables and all the html comment directives, and their parameters?

Also, it seems that requests are not stateless. For example when selecting a category in transfer, that value is not sent with the request. Instead you get back a $checked$ values from some internal state of the server.

Or really, I would love one or more json endpoints instead.
(Or do I just have to crawl thru the exported files and figure out things on my own?)