To find the blocks used in the page, there is a tool to activate in the admin panel.
But here you basically want to know which “action contoller” is used.
URLs are by default broken down this way :
/module front name[/controller name[/action[/paramkey/paramval[/paramkey/paramval]]]]
“Module front name” is not necessarily the same name than the module, but usually it is.
If no action, “index” action is used. If no controller, “index” controller is used.
If no module, the “home page” is used (configurable in admin)
For example : /customer/account/login/ triggers the “login” action in “account” controller from Customer module.
Note that many actions are “forwarded” to another action (it’s a kind of internal redirection)
If loadLayout() / renderLayout() is called in the controller, the “layout handle” used will be by default “module front name_controller name_action” (example “customer_account_login")