Hi Stephan,
The screenshot that you have attached is from the WebIDE, which already is in error state so it will not be loaded, if you want to check if it is loaded then just make it error free and run it in debugging mode.
Then check in the network tab if that js file is loaded or not.
You can see what is the error it is pointing by placing the cursor on the red cross that is shown in the screen.
For breakpoint you can add onInit function , and apply breakpoint over there, so you can check on it.
Also suggest you to declare the controller that you are creating.
With Regards,
Ramesh Shrestha