Logging on to iTunes Connect to upload a new version of an iOS app now shows a new section within "Contact Details" for an app.
According to Apple, "to offer your app on the Korean App Store, you must provide additional information that will be displayed alongside your app. Note that this information will only appear in the Korean App Store."
In particular you must give a full name, postal address, phone number and email address for you or your "trade rep", and these will be shown on your App Store listing in Korea.
Understandably developers, particularly one-man shops may have concerns about this. Previously it was necessary to provide a phone number but this was only visible to Apple, while showing developer's full addresses raises some privacy concerns. The fields are opt-in but Apple implies your apps will not be shown to users in Korea unless you provide the new contact details.