Once Link leaves the Great Plateau in Breath of the Wild, he'll unlock an exclusive sidequest called: [Xenoblade Chronicles 2]. Unfortunately for some fans, this doesn't mean Rex and the other XC2 characters will make an appearance in BotW. The sidequest was simply added as a collaboration between BotW and XC2. Completing it will net Link the Salvager Set, Rex's default outfit.
Players will need version 1.3.3 of Breath of the Wild in order to see the quest. This will automatically download when starting up BotW. Link will then need to visit three different areas at night. Despite being unlocked after the "tutorial mode," it's easier for players to complete this sidequest once they've explored most of northern Hyrule.
Salvager Headwear (Bridge of Hylia)
The first riddle is: The southern sky from the middle of the largest bridge.
While not very specific, the bridge this line is referring to is the Bridge of Hylia. Players can reach this by flying north from the Lake Tower. Stand in the middle of the bridge, but be careful: There are various enemies standing guard. It's recommended to wear one of Kilton's Monster Masks or Majora's Mask (DLC only) to keep them from attacking.
From the middle of the bridge, look up at the sky facing south. If it's past 9pm in-game, players will hear and see a red falling star. Watch for where it lands, and hurry on over to it. There will be a red chest containing the Salvager Headwear.
Salvager Vest (Skull Lake)
The second riddle is: The eastern sky from the skull's left eye.
This is referring to Skull Lake. If players haven't already done so, head towards Akkala Ancient Tech Lab. This is in the northeast section of Hyrule, on the other side of the Eldin region. Looking at the map, there will be a skull-shaped lake northwest of the Akkala Ancient Tech Lab. There's the Zuna Kai Shrine on the skull's "left eye."
From the Shrine, look up at the sky facing east and wait for the red star. It lands quite a distance away, and Link will need to do some climbing, so equip the Climbing Set and make sure Link has enough stamina. Open the chest to get the Salvager Vest.
If players haven't done so, drop into Skull Lake to meet Kilton. Speak to him to unlock the Fang and Bone shop. Kilton will only appear at night, so visit him after getting the Salvager Vest.
Salvager Trousers (Hebra Peak)
The third riddle is: The southeastern sky from the peak of the tall, pierced snowy mountain.
A snowy mountain could be in Gerudo Highlands or Hebra Mountains, but this riddle is specifically referring to the Hebra Mountains. There's a Shrine (Goma Asaagh) at the bottom of the mountain that Link can Fast Travel to if he's already Activated it. Melt the ice with a fire weapon or Fire Arrows, and go around the mountain (to the left) until Link is able to climb up. If players do not have the Goma Asaagh Shrine on their map, head west from the Snowfield Stable to reach Hebra Mountain.
Be sure to wear cold-resistant gear such as the Snowquill Set. Alternatively, Link can wear a level-1 cold-resistant armor while equipping a flame weapon to ward off the chill.
At the very top of Hebra Peak is a rock hiding a Korok. Pick it up to get the Korok Seed, then look to the southeastern sky for the red star. From there, paraglide down to where it lands to get the Salvager Trousers.
More Information on the Salvager Set
As armor, the Salvager Set may be unimpressive to some players. Each piece has a base defense of 5, but wearing them will increase Link's swimming speed. Wear all three pieces to get its Set Bonus, which gives Swim Dash Stamina Up. This means Link can dash in the water wiht X-button at the cost of less Stamina. The Salvager Set essentially has the same Set Bonus as the Zora Set.
Since this armor is DLC-exclusive, it can't be upgraded or dyed. Thus, it can be easily replaced by an upgraded Zora Set. If by some chance players sold their Salvager Set, they can buy a new one from a man in Tarrey Town so long as they have completed the [Xenoblade Chronicles 2] sidequest. This also applies to other DLC-exclusive armor such as Midna's Helmet or the Korok Mask.
The Legend of Zelda: Breath of the Wild is available for Nintendo Switch.