Tretta is just a name. It doesn't mean anything, it's the sort of thing you append to a product to make it sound better or cool. It's like saying "Zega" or "3000"; it's just a buzzword that sounds good or indicates an advanced option you wouldn't get with a standard <item>. Which makes me think it's either a new toy range or something with the TCG, although it won't be a new deck or something like that because most of the TCG names are at least partway meaningful ("advanced destinies" or "fossil" or something).
Whatever it is it probably won't be THAT important as they normally pick a meaningful name for games/TCG/manga..whatever. It could be a short-lived event or something.