The application you will be deploying is a wild west shooter style game.
Applications are often divided into components based on a logical division of labor. For example, an application might consist of a data-storage, backend component that performs the application's primary work and stores the results. The backend component is paired with a user interface, frontend component that accesses the backend to retrieve data and displays it to a user.
The application deployed in this tutorial consists of two such components.
The backend is a Java-based Spring Boot application. It performs queries against the Kubernetes and OpenShift REST APIs to retrieve a list of the resource objects that were created when you deployed the application. Then, it returns details about these resource objects to the frontend.
The frontend is the user interface for a wild west style game written in Node.js. It displays popup images which you can shoot, corresponding to the resource objects returned by the backend.