Hi,
This change will allow developers to add such capabilities when developing shipping plugins.
This actually comes from work done by one of our partners, Obsidev, who needed that capability to develop a shipping plugin for Mondial Relay. Work is still going on on that end.
As a user of HikaShop, it doesn't change anything for you for now.
However, if you can provide insights on why you would need something like that, it might give us some ideas on what to work on in the future for shipping plugins.