I've just begun the transition process from D7 to D8. I installed D8 and added a basic page w/ a menu link. I then began to explore the new D8 routing system and expected to find a .yml file that contained information about where to find the added page but I don't see it. This is not a added module so it doesn't have a moduleName.routing.yml.
I'm looking for a conceptual description of why this does or doesn't follow the new .yml convention.