Locked Chests can be found around the world.
Unlock them to get rewards.
There is 3 tier of chests : Rare, Epic and Legendary (see below)
Higher tier can give greater loots.

Rare Chest need 1 challenge complete, 2 for Epic and 3 for Legendary

Chest Locator help you to find some Locked Chests

The Chest Locator can also be used as an Ability Stone if you have the mod One Tool link installed.

Locked Chests emit light making them easier to find

When you open a chest, there is 4 different "challenge" to unlock the chest.
Each challenge and each answer are totally random, so there isn't 2 chest that get the same answer.

Config Loot Table:

The loot table can use other mods items.
There is 2 way to modify the loot table:

1: In game, if you are admin, you can use /lockedchests_admintool

2: You can also edit the file: ItemList.json | located at: \config\lockedchests

Exemple :

...
"8": "locked_chests:chest_locator",
"9": "minecraft:slime_block",
...

Config Generation:

You can configure many things in the file: lockedchestsconfigs.json | located at: \config\lockedchests

Here is the default config file:

{
"Locked Chests Main Configs :": "Doing changes only on values",
"----------------------------": "----------------------------",
"Chest Locator is unbreakable": false,
"Timer to unlock (Sec)": 8,
"Chests spawn only underground (will also make them rarier)": false,
"Rare chests generation (max 4/chunk)": true,
"Rare chests spawn chance (between 1 and 100)": 60,
"Percent loot 1st roll Rare chest (Between 1 and 100)": 100,
"Percent loot 2nd roll Rare chest (Between 1 and 100)": 5,
"Percent loot 3rd roll Rare chest (Between 1 and 100)": 0,
"Epic chests generation (max 2/chunk)": true,
"Epic chests spawn chance (between 1 and 100)": 40,
"Percent loot 1st roll Epic chest (Between 1 and 100)": 100,
"Percent loot 2nd roll Epic chest (Between 1 and 100)": 100,
"Percent loot 3rd roll Epic chest (Between 1 and 100)": 5,
"Legendary chests generation (max 1/chunk)": true,
"Legendary chests spawn chance (between 1 and 100)": 10,
"Percent loot 1st roll Legendary chest (Between 1 and 100)": 100,
"Percent loot 2nd roll Legendary chest (Between 1 and 100)": 100,
"Percent loot 3rd roll Legendary chest (Between 1 and 100)": 100
}

Feel free to use it in any modpack.
You can also join the Discord