This is one of the two new shoulder enchants added in Patch 7.3. One is available from the 聖光軍團, the other from 阿古斯守望. Both require Revered reputation.

This particular enchant yields 原始薩格拉斯精華, which is used to craft various items, as well as to upgrade crafted gear via 原始滅塵.

An important note is that the 聖光之寶 containers that drop from this enchant will drop from ANY Legion mobs (Broken Isles, Dungeons, Raids), not just those on Argus.

This is one of a number of shoulder enchants - this heralds the return of the shoulder enchant after there being none in Warlords of Draenor.

These enchants do not provide combat bonuses, but rather grant the chance to loot extra resource bags when defeating enemies in Legion outdoor zones. Most require various levels of reputation with a respective faction to purchase (as noted below).

Note that most of the enchants are consumed on use, meaning that enchanting a new set of shoulders will require that you obtain another enchant from the appropriate vendor, etc. The exception to this is 虛空恩澤, which is not consumed and can be used over and over again to enchant various shoulder pieces.

Below is a list of the various enchants available. You can click the coordinates for vendor locations on a map.

Enchant	Mobs Drop	Can Contain*	Source
執光者恩澤	聖光之寶	1-5 原始薩格拉斯精華	Reputation: Revered Vendor: 復仇者潔拉娜 Faction: 聖光軍團 Location: , The Vindicaar (Top Deck)
堅定者恩澤	阿古岩晶簇	10-20 朦朧的阿古岩	Reputation: Revered Vendor: 『崇敬者』托爾蘭 Faction: 阿古斯守望 Location: , The Vindicaar (Top Deck)
寶石追尋者恩澤	應有盡有的寶石袋	Various Gem Chips Uncommon gems Rare gems	Reputation: Revered Vendor: 佛里迪斯‧法隆 Faction: 法隆迪斯廷衛 Location: , Azsuna
採集者恩澤	收集到的貨物	10-30+ of various Fish 10-30+ of various Herbs 1-4 星輝玫瑰魔草	Reputation: Honored Vendor: 西爾維亞‧鹿角 Faction: 織夢者 Location: Lorlathil - , Val'sharah
屠夫恩澤	屠夫割下的肉	10-50+ 石皮皮革 10-30+ 雷鱗 10-30+ of various Meats 10-30+ of animal Crafting Reagents 魔能皮革	Reputation: Honored Vendor: 蘭莎‧灰羽 Faction: 高嶺部族 Location: , Thunder Totem, Highmountain
法力追尋者恩澤	法力氣息包	100-400 上古法力 5-30+ 阿坎納塵 1-6 地脈之光裂片 1-2 混沌水晶 1-2 上古治療藥水 1-2 上古法力藥水 Various Potions/Elixirs Various Flasks	Reputation: Honored Vendor: 首席秘法師薩莉瑟拉 Faction: 夜落精靈 Location: Meredil - , Suramar
回收者恩澤	回收的護甲	10-30+ 魔岩 10-50+ 脈石礦石煉獄硫磺 Chance for Uncommon or Rare armor Chance for Grey vendor trash	Reputation: Revered Vendor: 瓦德瑪‧探風者 Faction: 華爾拉亞 Location: Valdisdall - , Stormheim
血獵人恩澤	血獵人的獵物	1-5 薩格拉斯之血	Reputation: Revered Vendor: 馬林‧刃翼 Faction: 看守者 Location: , Dalaran
附魔肩膀 - 拾荒者恩澤	回收的衣裝	10-40 夏多雷絲綢	Crafted by: Enchanting - 拾荒者恩澤 Materials: 地脈之光裂片 X 2 Formula Source: Quest - 暗心灌木林：光芒散盡
虛空恩澤	Any of the following: 應有盡有的寶石袋收集到的貨物屠夫割下的肉法力氣息包回收的護甲血獵人的獵物回收的衣裝聖光之寶阿古岩晶簇	Any of the contents of the appropriate bags, as listed above	Vendor: 瑟里歐斯 Cost: 50 奇特的硬幣 Location: Dalaran - , Dalaran
寵物師恩澤	一堆寵物用品	6-10 亮晶晶的寵物吊飾 2-4 戰寵繃帶 2-4 魔法小點心 2-4 魔法寵物餅乾 2-4 寵物裝扮組小寵物點心 Various Flawless Battle Stones Chance for Grey vendor trash	Vendor: 德雷穆斯 Location: , Dalaran
製造師之助	扣鏈寶箱	Various Engineering vendor materials Various Engineering crafted gadgets 1-2 堅硬的魔化玻璃 Chance for 880 Engineering goggle schematics	Vendor: 荷巴爾特‧繫錘 Profession: Engineering Location: , Dalaran

NOTES:

The "Can Contain" column denotes the various possible items that can be found in the looted reward caches; some materials have a lower chance than others to be looted.

評論來自 Cappilon

So is the drop rate super low? I've had it on my shoulders for a couple of days now and have yet to see any Light's Fortune drop.

評論來自 BuckyDK

Thought this meant you could get those Rep tokens from mobs.

Its just #$%^in primal sargerite, the most useless trash..

評論來自 Mookosh

After Shadowlands pre-patch (9.0.1) and doing some testing. I have confirmed the Legion shoulder enchants will work on the following:
* Legion content shoulders, including Legion legendaries, but only on level 45 or lower characters
* profession crafted green/blue BFA shoulder for level 45, but only on a level 45 character
* profession crafted green/blue BFA shoulder for level 45 on a level 45 character
* Heirloom shoulders, but only on a character level 45 or lower.
* Azerite shoulders from the War Campaign quest lines (the baseline iLevel 58 ones) on level 45 characters (I have an xp locked 45 speed farm druid who got their Heart of Azeroth before the Shadowlands released, with scavenger and bloodhunter on two pairs of Azerite shoulders and they continue to proc killing on the Broken Isles). These must be enchanted BEFORE activating the +5 item level azerite trait on them, as those additional item levels will push it above the maximum for the boons. ~~Unfortunately they can't be re-enchanted with a different boon as it gives the ... too high level message, but that character still receives cloth satchels and bloodhunter quarries.~~. To change boons on the Campaign Azerite shoulders, you will need to go to the reforger in Boralus or Zandalar and reset the traits. Then you can apply a new boon before activating the final +5 item level trait.

It is worth noting, existing boon enchants on shoulders that are now too high for it to have been applied will no longer function despite previously proccing before 9.0.1. The only exception I've found is those on level 45 characters.

Edit: Where prior to the 11/3/2020 reset, I was getting boon procs on my level 50 characters using enchanted Legion legendary and legion content crafted/dropped shoulders, I am now getting no procs after 2+ hours of additional testing.
I tested again on my xp locked level 45 character, and continue to receive boon drops of all kinds with a wide variety of shoulders from Legion Legendary, to Legion crafted, legion armor token created, heirloom AND even BFA level 45 green/blue upgraded crafted shoulders.

It appears all of the boon enchants have some kind of strange character level restriction attached to them in addition to the actual shoulder item level now.