It's a fried chicken sandwich with garlic parmesan dressing and a bun that has cheese on the top. Yes, on the top of the bun. According to the KFC Philippines Facebook page, it's only available in that country for now, but if KFC does know anything, it knows to bring its most gluttonous items to the U.S. before long (see: Double Down Sandwich).
One day, the Cheese Top Burger will be ours, 'Murica. One day.