I remember that - it was when Passbook was first released. That app was useful for minting the completed pass, but required a lot of JSON and handholding because iOS needed to validate the result against the Sinatra code. Having not yet downloaded this, but having played with the new "Create pass" feature in wallet, it seems like some of those validations may have relaxed and this is a tool that makes the rest of the work easier, too. Glad to see it from Apple.
