Is the track a collaboration or does it have an original writter?

By the way in the link i posted in the previous thread there are 2 versions starting at 50:40
[url=https://www.youtube.com/watch?v=ZR4fIYGQmF4]https://www.youtube.com/watch?v=ZR4fIYGQmF4[/url]
Man! what a powerfull melody/instrumentation. How on earth they skipped that from featuring it on an album?