Notifications and focus - Does this have a .plist?

There is a folder in ~/Library/Containers for Notification Center. Inside, there is a path to a plist file for Notification Center UI. I personally have not tried to change any settings for Notification Center, except for creating configuration profiles that turn on notifications for specific apps. If you're looking to do that, then a configuration profile would probably be a better way rather than directly manipulating the plist files.