Night mode is an automatic setting which takes advantage of the new wide-angle camera that's in the iPhone 11 and 11 Pro models. It's equipped with a larger sensor that is able to let in more light, allowing for brighter photos when the light is low.
macOS Catalina Now Available
Amazon Prime Video Currently Unavailable in App Store Across iPhone, iPad, and Apple TV [Update: It's Back]
Apple deferred comment to Amazon, which has yet to respond to our email. We'll update as we learn more.
Update: MacRumors has been informed this was a technical issue and the app should be back up shortly.
Update 2: Amazon Prime Video has returned to the App Store.