I'm new to Odoo 9 and want to learn the basic. Given i click on top menu Purchases and then on menu item i click Purchase Order.

The url for this menu is http://localhost:8069/web?debug=#page=0&limit=80&view_type=list&model=purchase.order&menu_id=223&action=289.

With this url how do i know which xml and python file i can modify if i want to do some modification? and also how do i know the name of the view to be inherited?

I know rails and in rails it can be found on the routes file (routes.rb). I'm not expecting the exact same way but there should be a way to do this since all i know Odoo development is about modifying it.