The issue focused on how to get an idea from the user about the state of the system.

A user interface is the user interface for the data.

Data is an abstract representation (a set of values) for a specific application.

User interactions are user interaction events that can be sent and received by the user.

A system is a set of data structures (objects) that represent a specific data set, e.g., user data, user interactions data, and so on.