List contents of NSUbiquitousKeyValueStore

Is there a way to view the contents of an app's NSUbiquitousKeyValueStore? I was expecting to find a property or method that listed the keys, or maybe a web app like the CloudKit Dashboard.
Right after posting this I thought of a crude way to do it: dive into the app's sandbox on a simulator...

/Users/«USER»/Library/Developer/CoreSimulator/Devices/«DEVICE»/data/Containers/Data/Application/«APP»/Library/SyncedPreferences/«BUNDLE».plist

Good enough for debugging, but having a keys property would be better. I mean, if I need to clean up disused prefs I had really better never forget which keys were used when I shipped.
List contents of NSUbiquitousKeyValueStore
 
 
Q