Grab all nine and unlock a new mission
Both Sony and Microsoft have their own platform-exclusive missions for Metal Gear Solid V: Ground Zeroes, and you'll have to do a bit of legwork to unlock them. Basically, you'll need to grab all nine XOF patches hidden throughout the main mission, then complete the main objectives.
Here in this video I'll show you the location of every patch, and pause for a second to also show it on the iDroid map. If you're wondering how to get the second patch at the start of the video, just go prone, and press in the left stick to roll from side to side constantly until it falls out.
XOF patch progress only saves at checkpoints -- so if you get a game over, you may need to recollect a few.