The category type discerns whether the policy covers the sale of motor vehicles (via eBay Motors), or the sale of everything except motor vehicles.
Each business policy can be associated with either or both categories ('MOTORS_VEHICLES' and 'ALL_EXCLUDING_MOTORS_VEHICLES'); however,the 'MOTORS_VEHICLES' category type is not valid for return policies–return policies cannot be used with motor vehicle listings.
Sellers can create multiple policies for any categoryTypes.name and marketplaceId combination. For example, you can create multiple fulfillment policies for one marketplace, where they all target the same category type; however, only one can be default at a time.
If this value is set to true, it indicates that this policy is the default policy for the associated categoryTypes.name and marketplaceId pair.
Note: eBay considers the status of this field only when you create listings through the Web flow. If you create listings using the APIs, you must specifically set the policies you want applied to a listing in the payload of the call you use to create the listing. If you use the Web flow to create item listings, eBay uses the default policy for the marketplace and category type specified, unless you override the default.
The category type to which the policy applies (motor vehicles or non-motor vehicles). Note: The 'MOTORS_VEHICLES' category type is not valid for return policies because motor vehicle listings are non-returnable via eBay processes.