Can you link the source? The last I saw, which was Microsoft at Gamescon followed by that terrible interview Phil a Spencer did with Eurogamer, Microsoft are publisher on Xbox 360 and One. That's all.
http://en.wikipedia.org/wiki/Rise_of_the_Tomb_Raider
MS is now listed as a co-publisher.
The original source
http://www.polygon.com/2014/12/9/7359861/rise-tomb-raider-microsoft-pubslish
Microsoft is publishing for the XBO and X360.
Square Enix will be publishing the PC version. And
if there are other versions they will publish it as well. However...
"Yes, Microsoft will be publishing Rise of the Tomb Raider on Xbox," a Microsoft spokesperson said. "Similar to how we worked with Capcom on Dead Rising 3 or Harmonix on Dance Central, we're very excited to partner with the amazing team at Crystal Dynamics to bring Rise of the Tomb Raider in holiday 2015, exclusively to Xbox. Both our team and the Xbox community are huge fans of the franchise and we can't wait to share more on the game in the future."
Dead Rising 3 - XBO, PC
Dance Central - X360
If you look closer at Dead Rising 3, you'll see a similar situation with Microsoft as co-publishers. Microsoft was the publisher for the XBO version. Capcom was the publisher for the PC version as well as the Japanese XBO version.
Also, note that Microsoft was also just a co-publisher for Dance Central. MTV games was the other publisher.
In fact, for any Xbox exclusive this generation which has had a PC release. Microsoft has only been a co-publisher. As the PC versions have been published by other companies. Ryse PC was Crytek and Deep Silver, for example. Titanfall was EA on PC. All of them were time limited exclusives (except Titanfall which launched simultaneously)...just like the upcoming Tomb Raider game.
Wording is still vague. So it's possible it'll appear on PS4, but I wouldn't hold my breath. Especially if the contract is similar to the one they had with Capcom (who had the rights to publish on other platforms, as long as they were not Playstation related). But so far, when MS has been listed as a co-publisher, the games haven't appeared on a competing console.
Only time will tell as neither SE nor Microsoft are going to disclose details of the publishing agreement. Just like neither Capcom nor Microsoft are going to disclose details of the Dead Rising 3 publishing agreement.
So time limited exclusives for Ryse and Dead Rising 3. Time limited exclusive for Tomb Raider...
I'd be willing to go out on a limb and say all XBO exclusives are time limited. Just that when time expires. PC may get a version (no guarantee), but will anyone else?
Regards,
SB