Interface
GuestShipmentEstimationInterface
Magento\Quote\Api\GuestShipmentEstimationInterface
What it does
This interface is used to estimate shipping costs and methods for guest customers (non-logged-in users) during checkout.
It extends the base ShipmentEstimationInterface to provide the same shipping estimation functionality but specifically for guest carts.
Developers would use this when implementing or customizing shipping rate calculations for guest checkout flows.