en-CA
Fragment of a discussion from Support/LiquidThreads
GerardM, please get some context. Using SieBot (Special:Log/SieBot) Siebrand deleted every message for the en-CA locale (The correctly translated en-CA locale is now entirely empty) saying "en-ca not needed in MediaWiki.". en-CA has differences from both en-US:en and en-GB, and the only messages that were translated were the ones that were different from en-US.