Thank you for your answer. I agree with you, we should interpret localized as fully localized. Otherwise this could be misleading for the users. I will not list any other language in the CFBundleLocalizations, so that the App Store shows my app as available in English only. And as you suggested, I will list the languages available for the subtitles in the app's description.

Thank you very much for your answer. This is very helpful. Indeed I didn't try, I'm still using Xcode 12.0.1. This is because I don't trust Apple that much when it comes to supporting older OSes and devices. And I do care about this, as a developer.