I've never been able to find any information concerning what enhancements it has.
Even this Reddit post by UbiSoft goes nowhere.
I've been doing some digging, but that metric is going to be hard to determine, since there have been X updates for titles that were released before the system was released (The Master Chief Collection, for example).
Going by Wikipedia's "
List of Xbox One Games" entry, there are 1,907 titles released for the Xbox One (across all regions). There are 364 Xbox One titles in the OP. 272 of them feature "2160" in their entry*. Ignoring a small margin of error for a whole myriad of different reasons, here's some fun statistics based on those numbers.
19.09% of all Xbox One titles feature an X Enhancement of some kind.
14.26% of all Xbox One titles are 4K, including dynamic rendering.
74.73% of all Xbox One titles in the OP are 4K, including dynamic rendering.
* My search grabbed titles like Attack on Titan 2, Quantum Break, and Unravel 2, which all are rendered below 2160p but have some element to them that is in 2160p (like Unravel 2's lighting is rendered in 2160p).
I don't know the answer to that, but it's in Microsoft's official Xbox One X Enhanced list. Yesterday I took some time and compared their list against mine and updated the OP with any differences. Microsoft's list isn't the Bible, as I've seen errors/omissions in there in the past, so it could definitely be wrong. However, looking at the Microsoft Store entry, it doesn't list "X Enhanced" and I've found that to be a more accurate record than Microsoft's list.
So, if anyone with the game can post screenshots/impressions that would be helpful.