I don't know if anyone has figured out what he meant and I don't really feel like digging through a bunch of forum posts. I can guarantee you he meant "Platinum end"(platinum endwalker, get it?) the manga/show. If you have seen/read it you will probably understand if you have finished endwalker, or go give it a view or read and see if you find the links to xiv that I found.

I can only hope someone that can get an answer from Yoshi actually sees this, and if it has already been guessed by someone then grats to them.