The Debugger allows you to see your application variables. It allows you to see what value is being stored and where the value was set.
Open the debugger by clicking on the bug icon in the Designer Rail on the left hand side. This will show you a list of all the variables within your application. It will show you the value being stored as well as where the value was set.
You can use the search bar at the top to narrow down the list.
The refresh button allows you to refresh the stored data as you work withing your application.