It looks like a second fan or something. 
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As a matter of phrasing, the fact that you aren't sure what something is doesn't make it strange. :) These are present on many (most) turbofan designs and have been for decades! – egid Sep 04 '15 at 18:04
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Those are Outlet Guide Vanes / Fan Exit Guide Vanes. They prevent the flow (bypass flow in this case) from rotating. The these vanes do not rotate, they are fixed to the housing. They also provide structural support.
Because there is no energy lost on the rotation of the flow the efficiency is increased.
DeltaLima
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1Indeed they are present on the GE 787 engine also of course. http://www.bloomberg.com/news/articles/2013-11-25/boeing-warns-of-ice-risks-for-ge-powered-787s-in-storms – Greg Hewgill Sep 03 '15 at 22:12
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Sorry I reviewed the pic it did actually have outlet guide vanes. My apology. – Ethan Sep 03 '15 at 22:21
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@Ethan no problem, I see you update your post, I'll update the answer. – DeltaLima Sep 03 '15 at 22:22
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1@Ethan: How engines are assembled by Rolls Royce, a good documentary on the Trent 1000 with many details on what is inside the casing, and for sure many (good) questions :-) – mins Sep 03 '15 at 23:27
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@mins The GE and Rolls Royce engines are almost exactly alike on the 787, have the chevrons on the end, both have outlet guide lines, and also similar thrust. Its pretty weird. I will make sure to watch the documentary also. – Ethan Sep 03 '15 at 23:33
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@Ethan: This is the part you are talking about, being welded. In this video. Enjoy! – mins Sep 03 '15 at 23:34
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@mins I'm just saying the engines are almost alike. I don't want to get a warning again, so this will be my last comment. – Ethan Sep 03 '15 at 23:36
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1The exit vanes also extract a little amount of thrust from the flow by converting some of the rotational energy into a forward force on the vanes. – Peter Kämpf Sep 04 '15 at 11:21
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1@PeterKämpf That is indeed how the recuperated energy manifests itself. – DeltaLima Sep 04 '15 at 11:26
