Auto or home insurance - which one which covers theft of items from your car?

If your personal property is stolen from your car - think sports equipment, clothing, laptop, shopping purchases - do you know what's covered by your auto insurance policy and what isn't?

Items attached to your car. like roof racks and baby car seats are covered by your auto policy.

But if the fancy leather jacket that you left in your car is the victim of a smash-and-grab you'd better have a home insurance policy in place.