As part of the ramp up to the release of Xenoblade Chronicles 2 early next month, Nintendo has added a new sidequest and armour set to Breath of the Wild. The new armour set is called the Salvager armour set, and is themed around the outfit worn by Xenoblade 2 protagonist Rex.
The new quest, which will simply appear in your quest log as Xenoblade Chronicles 2, is marked in the quest log as being a promotional quest for the new upcoming game. The quest comes in three parts, one for each piece of the new armour set, and tasks players with finding very specific parts of the world based on vague descriptions, looking to the sky to see a red shooting star, then following it to the location of a chest.
Here is the clue given to find the Salvager Headwear:
The bridge being referenced is the Bridge of Hylia, South East of the Great Plateau, so head to the very centre of that bridge at night and look to the sky. Follow the shooting star to your first chest.
The second piece of the armour, the Salvager Vest, bears the following description of where to locate it:
The skull being referenced here is Skull Lake, the lake in the North East of the map shaped like a giant skull. If you've unlocked the Zuna Kai shrine as a warp location, this is exactly where you need to be at night to see the second red shooting star, which you can follow to the Salvager Vest.
The final piece of the Salvager Armour set, the Salvager Trousers may be the most difficult to physically reach. Below is the description of where to find them given in game:
The snowy mountain being referenced here is Hebra Peak, in the north west corner of the map. If you keep zooming in the map, the name hebra peak will appear to coincide with a very specific peak on the map, west of Coldsnap Hollow.
From there, look to the south east at night to see the final shooting star, which will lead you to the Salvager Trousers.
And with that, you should now have the full Salvager armour set. Good luck, and happy cross promotional gaming.