kCFBundleDevelopmentRegionKey
The name of the development language of the bundle.
Declaration
let kCFBundleDevelopmentRegionKey: CFString!Discussion
When CFBundle looks for resources, the fallback is to look in the lproj whose name is given by the kCFBundleDevelopmentRegionKey in the Info.plist file. You must, therefore, ensure that a bundle contains an lproj with that exact name containing a copy of every localized resource, otherwise CFBundle cannot guarantee the fallback mechanism will work.