Sizes

Sizes reduces the time it takes to evaluate all of our app's possible device sizes, orientations and font combinations. With Sizes we'll avoid launching all the supported devices simulator, running our app and navigating through each screen manually which not only takes a lot of time but its also highly error-prone since we sometimes forget to test one particular combination and we ship a screen with a layout bug to the App Store. Xcode 11 introduced Previews which is a fantastic way to quickly validate your UI in multiple scenarios just like Sizes did. If you'd like to know more about Xcode Previews I recommend this WWDC session. You can even use Previews with UIKit so there's no reason to stick to this library.