Did you know? When a Google Apps Script project containing multiple ‘files’ is run, the entire script is ‘loaded’ and run. That might include what I call Phantom Code: script content that you don’t intend to execute. This situation is more likely when you are using the recommended practice of separating your code into different gs files, each focused on a different concern.
Problems might show up as unexpected behaviours, or it might be benign but contribute to your script execution limits and slow your scripts.