It selects which Root Planner environment Sprwt talks to: Live (default, api.rootplanner.io), Beta or Development. It also changes the links in the Customer Sync table, which open the matching Root Planner dashboard (my.rootplanner.io, my.beta.rootplanner.io or my.dev.rootplanner.io). Leave it on Live unless Sprwt support asks you to test against another environment. This setting only appears on the super-admin system Config page (System > Root Planner) and in the onboarding configuration step, not in the client Configuration screen.