Not sure if this is the right place to ask, but does every function of a site or application that has some user-facing component to it need to be in a page, i.e. in the admin site content tree?
For example, if I have a module that supplies an AJAX form item, does that module need to supply a page in the site structure to serve the AJAX requests? Or can user-serving URLs bypass the site structure tree completely and just go direct to a module?
It doesn't need a page, you can simply have a plain jane controller which returns the data. Something like AjaxController extends Controller then you can call functions like site.com/AjaxController/function or to make it nicer you can add your own Director rules to make a 'nice' url like site.com/ajax/function which uses the AjaxController class