This routes-trick is my starting point as well on web apps. The next place I try to understand is the persistence layer - be it the a database scheme or models

This routes-trick is my starting point as well on web apps. The next place I try to understand is the persistence layer - be it the a database scheme or models working against remote APIs. Building a mental model of the the data (around which the app surrounds) serves as a map for the rest of the code tour.