Readonly
Optional
Object containing the Custom Fields fields for the ShippingMethod.
Required if at least one Custom Field is defined as required in the `fieldDefinitions` of the referenced [Type](ctp:api:type:Type).
Defines the Type that extends the ShippingMethod with Custom Fields. If absent, any existing Type and Custom Fields are removed from the ShippingMethod.
Object containing the Custom Fields fields for the ShippingMethod.