. "proprietary" . "closed" . "is not allowed" . "restricted" . "within their systems" . "authorization" . "regulation" . "generally restricted to installation through the App Store" . . "closed platform" . "Closed platform" . . . . "\\\"walled garden\\\"" . "ecosystem" . "walled garden" . "Closed platform" . "walled-garden" . . "walled gardens" . "monitored" . . .