No Kamgawa RPG books in the Platinium or Silver edition, just cards and accessories.
but there is some new info on Kamigawa, Sagas confirmed, Legends matter set confirmed, Spirit Dragons confirmed, Ninjas confirmed, but most of the mechanics from OG Kamigawa are not returning (leaks from elsewhere show that Channel is an exception to that, it's on a Legendary Land), and it fantasy based Cyberpunk, the Sci Fi part is an illusion, as in the Cyber part is powered by some kind of alternate none Kami based magic, not electricity.
Also in addition to short fiction, they will have short histories, this is they said a more fiction/story focused set, it is not a surprise given we got two stories, released together so far ahead of the set.