I'm curious why you'd use the DOM instead of making API calls to the server. If Google can do it as part of their UI surely a 3rd party script can too. Is the API more complex than the frequently changing DOM?
Most email data related methods are making the API calls. The DOM is being used for methods like checking if a user inside an email or if the user has preview panes enabled. Since the primary goal of the library is to aid with chrome extension development, checking items in the DOM is quicker.
