According to 9to5Mac, the name Kit is an acronym for “Keep In Touch” and apparently works in tandem with Facebook’s already existing Messenger app. You still need to link Kit to your Facebook account, but you’ll then be prompted to pick out who you wish to communicate through the app from your Messenger list. From this point onward, all messages sent through Kit are sent through Messenger, to which there are a few methods. Off the bat, Kit allows you to send voice recordings or use dictation to translate speech-to-text. Needless to say, Facebook says that Kit also comes with several other features, including the ability to scan a QR code on your Apple Watch, as well as notifications, obviously.
Kit is downloadable for free via the Apple App Store for Apple Watch, although at the time of writing, our search for the app on the local storefront hasn’t bore fruit. On that note, Facebook says the app is still propagating. In other words, if you don’t see it yet, just be patient. (Source: 9to5Mac)