Great extension.
Expect it to get even better in the future.
Youtube would not be the same without your extensions for managing subscriptions and playlists.
Thank you very much for your work, providing the functionality Youtube should natively provide ( but doesn't, only god knows why ! )

Would be better if it had a way to auto put videos from the sub box into your playlist as soon as there uploaded. Such as setting one or more channels to an playlist and any video they upload go right into the playlist.