Those are iOS Simulator runtime disk images (the full OS bundles Xcode downloads for testing). Each is ~9 GB under /System/Library/AssetsV2/com_apple_MobileAsset_iOSSimulatorRuntime.

Those are iOS Simulator runtime disk images (the full OS bundles Xcode downloads for testing). Each is ~9 GB under /System/Library/AssetsV2/com_apple_MobileAsset_iOSSimulatorRuntime.

Safe to delete any you no longer need—Xcode will redownload if required later. Prefer Xcode > Settings > Components (delete under Other Installed Platforms) or `xcrun simctl runtime list` then `xcrun simctl runtime delete <build>`. Orphaned ones can be SIP-locked and harder to remove.