Indeed, it is extremely clear: by not saying "manufactured in Japan", the words "developed in Japan" tell you that they drew up the designs for the CPU in Japan, and then sent those designs off to a fab outside Japan for actual manufacturing. Then they bring those CPUs back to Japan, so that the server can be manufactured in Japan even if the server components are not.

That manufacturing step may change in the future, but right now that CPU is not "Made in Japan", it's only "Designed in Japan".