String format for CFBundleDevelopmentRegion (info.plist) for App Store display

Question

I work for a company that creates apps for the Japanese iOS App Store. Our only supported language is Japanese.

We selected Japanese as the "default language" in iTunes Connect, but when our apps appear on the App Store, they have the problem shown in the screenshot (the language is listed as English).

It's been suggested to me that setting the CFBundleDevelopmentRegion in info.plist will solve this, however I can find no mention anywhere in Apple's documentation about what format the language/region string should take. There are numerous standards, several of which are supported randomly by iOS in different places (JP, JA, JPN, JAPAN, JAPANESE etc.) and I've not been able to find an authoritative answer by googling. We think this may be correct

<key>CFBundleDevelopmentRegion</key>
<string>Japanese</string>

but would appreciate it if someone could confirm or suggest a better answer, as we don't want to go through a trial and error process, given that app store approval takes a week to get a result for each attempt.

Please note: This is not a localization question. We don't want to support additional languages. We just want to set the base language to Japanese so that the app is correctly displayed in the store.

Answer 1

I wrote this question because I sent off a technical support request to Apple a few days ago, but hadn't heard anything back yet. As luck would have it (typical!) barely an hour after posting to SO, Apple responded, so I guess this is the authoritative answer (the second part about no localization folders is what we want):

The value of the Languages field in iTunes Store is created by scanning the localization folders in your application bundle. If you want it to show "Japanese" only in the store, you need to make sure there is only "ja.jproj" folder in your application bundle. If you don't even have any localization folder, you can select plist file of your project in Xcode, and set the "Localization native development region" by selecting "Japan" from the candidate list supplied by Xcode plist editor, by doing that the CFBundleDevelopmentRegion key will be set to "ja_JP" (language_local), you can also follow ISO 639-1 or 639-2 to use "ja" or "jan."

I will mark this as answered in 2 days when the time limit expires.

Additional edit: I suspect the Apple employee meant "jpn" in regard to ISO 639-2, as "jan" is not a valid code, but jpn is.