You can get these patches during the mission "Ground Zeroes". Collecting all XOF patches will unlock the Extra Ops missions Deja Vu (PS3/PS4) and Jamais Vu (Xbox 360/ Xbox One).
1: As soon as you start the game, lie down on the ground and roll around. Keep doing this until a scene is triggered, showing how the patch ended up on Snake's back. Pick it up afterward.
2: From the starting point, turn around and check the ground near the cliff to find this XOF patch.
3: Garbage mound, south of the west refugee camp.
4: On top of a generator, north of the warehouses.
5: In the drainage outlet, beside some stack of supplies east of the administration building's main gate.
6: In the black patch on the ground, between the second and third helipad.
7: On the exhaust vent, in a ledge just past the northeast red door of the administration building.
8: On the roof of the guard house north of the prison camp.
9: On the ground, under the prison camp's gate.
[spoiler] [i][/i] I Wana Know What Means XOF? [/spoiler]
how do i open the deja vu mission ?