The playfab portal itself refers to the term 'Studio' but some of the literature keeps referring to 'Publisher'. For example look at the 'Publisher Data' section in the following article:-
https://api.playfab.com/docs/tutorials/building-blocks
So I guess publisher is identified by a playfab login account, that can have multiple 'studios' and each of the studios can have multiple 'titles'. Does that sound correct? If so, 'Publisher Data' can be accessible from any game belonging to any studio of the publisher?