DemoLoop

Screen Saver is an app that comes with iOS and iPadOS devices in Apple Stores, Best Buy, etc. It is created as the devices are always on to preview the product itself, and prevent burn in. This app launches every time the device is inactive. If you hold 3 of your fingers on the display at once, it brings up a secret menu. It is also known as DemoApp.app, and plays the file at Root:/private/var/mobile/Demo.mov. The contents of that file vary between device, time, and OS.

Installation
You can install the app illegally by pasting itms-services://?action=download-manifest&url=https://demoupdate.apple.com/install/4.7/demoupdate.plist in your URL bar. You can also get the .ipa file by clicking this link. Pasting itms-services://?action=download-manifest&url=https://demoupdate.apple.com/install/4.6/demoupdate.plist into the url bar brings up an older version and you can download the ipa here.