meta-car provides a number of interactive tools with CAR files.
swan-client meta-car -h
NAME:
swan-client meta-car - Utility tools for CAR file(s)
USAGE:
swan-client meta-car command [command options] [arguments...]
COMMANDS:
generate-car Generate CAR files of the specified size
root Get a CAR's root CID
list List the CIDs in a CAR
restore Restore original files from CAR(s)
extract Extract one original file from CAR(s)