The app uses several web components. This document explains how they are set up and how to update them.
The article view uses a server-side response from our Page Content Service with additional local js and css files for further customizations. These local files live within the Wikipedia/assets folder in the project. You can update these directly and commit the changes.
There are other smaller web components in the app, such as the About view. These live in the Wikipedia/assets folder and can be updated directly.