I'm seeing a lot of disk space (e.g. over 20 GB ) taken up by SwiftUI previews under this folder: ~/Library/Developer/Xcode/UserData/Previews Arbitrarily deleting the contents of this folder seems to stop previews from working. xcrun simctl delete unavailable does not seem to work on this folder, as well. There is a device_set.plist file in the Simulator Devices sub-folder, and some of the sub-folders are not listed in this file. In general, has anybody figured out a safe way to cleanup this folder or heard from an Apple engineer on what exactly goes on in there? Does Xcode actually manage the contents of this folder by adding / deleting devices when you add / remove simulator runtimes?