Vaadin protocol specification

Hi All,

I can not find Vaadin protocol specification. For example I see the following request to Vaadin in browser:

{"csrfToken":"aad66221-9f91-466f-9e9e-8e7dc679cce1","rpc":[["0","com.vaadin.shared.ui.ui.UIServerRpc", "resize",[390,1440,1440,390] ]],"syncId":0,"clientId":0,"wsver":"8.0.2"} so I need to understand what is going on here and in other requests. So is it opened or looking at vaadin source is only way?

Thx in advance