If based on the ea888 gen3+ head, the manifold is split two by two cyl and cast in the head incl water cooling. Usually the turbo is just bolted straight on without twin scroll, these longer pipes will further help seperating the pulsations of each 2cyl bank and thus help VE/scavenging especially under low/mid rpm when pressure fronts have longer time to travel back before the next one comes. Without actually using fully sepeated twin scroll turbine split housings that aren't as efficient and probably not allowed anyway.
Something like that...