If you put this property inside the l10n object, then the notification id will be localized at startup time along with the title, and you'll get a notificationID: 'Timer: off' in the outer object.  But that is no longer an ID, it is a localized message, so it doesn't really make sense to do it there.   You are localizing the messages every time a notification is displayed (which is fine) so you don't need to use the l10n object get localization in advance.

So please move the notificationID properties so they are not in the l10n object. (My preferred solution).

Or put them all in the l10n object, change their name to 'notification' and remove the localization code from the notification view.  Right now you have a mix of these two approaches.