This is a sample app demonstrating how to open an app from a Control Center widget bundled with that app, based on help kindly provided by Brian Mueller here. Important notes:
- The file that contains the control widget has to be included in both the main app target and the extension target (see this thread).
- The point of the URL is only to launch the app. The actual mechanism for communicating to the app what screen to open is, in this example,
UserDefaults.