At WWDC 2017 Session 201 What's New in Cocoa Touch, around the 33:50 mark, it is stated that "By incorporating [icons] in Asset Catalogs, we're now able to have them participate in the app thinning, which will significantly lower your app's footprint. So, this is a really exciting thing to adopt, and it will be adopted by default in new projects in iOS 11. You can opt into it in existing projects by adding a key to your Info.plist."
What is the key you need to add in your Info.plist to enable app thinning for icons in Assets Catalogs in your existing projects? I'm not seeing it defined in the Information Property List Key Reference.
You need to use an asset catalog for your app icon to participate in app thinning. Its not in info.plist but a setting at the target level on your project file.
来源：https://stackoverflow.com/questions/45665987/opt-into-app-thinning-for-icons-in-asset-catalog-in-existing-project