The following footage has been leaked from a vetted source as a cut-scene from Halo on Xbox ONE featuring the forerunner symbol at the end. Cortana is also featured in the footage. Be sure to remember this game is scheduled for 2014 on Microsoft’s next-generation game console Xbox ONE and is titled “Halo” not “Halo 5” as it is sometimes referred to by developer 343 Industries and their massive Halo fan-base.
What does it all mean?
That Cortana is still alive or revived and that this scene might be after what ever causes Master Chief to lose his chest piece and get the huge scratch on his helm. It looks like some type of dark forerunner room with obvious forerunner colors, in blue and red plus the fact Cortana is blue also symbolizes this.