Answer by Jano for Analysing Assets.car file in iOS

Run Apple’s assetutil:

xcrun --sdk iphoneos assetutil --info Assets.car

you’ll get a JSON description of each item in the file. Something like this:

  {"Height" : 60,"Scale" : 1,"RenditionName" : "D3801CE9-19F1-4CE9-97C6-7E1EFFFCAE89","AssetType" : "Vector","SizeOnDisk" : 10822,"Name" : "mailbox","Idiom" : "universal","Width" : 99  },

Note the line "SizeOnDisk" : 10822.

This tool performs limited .car manipulation, run man assetutil for details.

The Assets.car seems to be a proprietary Apple’s archive that first appeared in iOS 7. A few utilities are able to extract its contents using the private class CUICatalog of the CoreUI framework:

• acextract
• ThemeEngine
• iOS Asset Extractor
• Asset Catalog Tinkerer

There is also an app that reads .car files: crunch 9$, 15 day trial

Running strings Assets.car returned

@(#)PROGRAM:CoreUI  PROJECT:CoreUI-475.1.1IBCocoaTouchImageCatalogTool-9.0

Running find inside Xcode-beta returned /Applications/Xcode-beta.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/Library/Xcode/Overlays/IBCocoaTouchImageCatalogTool, which is a simulator executable (i386 + x86_64). Didn’t investigate any further but I bet that this tool could open .car archives if you run it inside the simulator.