The mod for Baldur's Gate 3 adds legendary items to the game, including dual-wield hand crossbows.

Item Descriptions:

The following legendary items have been added to the game:

Pain Chain
The Pain Chain is a weapon blessed by Loviatar, capable of invoking holy wrath upon enemies. However, great power comes at a cost, and players must pay an epiphany to earn Loviatar's blessing.

The chain includes a bonus action that deals damage to the user but then triggers a very powerful attack on the enemy. Just be careful not to kill yourself.

Poison Dagger
Forged by the Drow elves in Menzoberranzan, this blade poisons everything it touches, but its wielder gains immunity to poison.

This weapon deals additional poison damage and affects enemies with it. It has stat adjustments.

Maiming Dagger
A dagger designed for quick incapacitation of enemies through the introduction of a mixture of chemicals and magic.

This dagger deals various types of damage, and you can also use a critical on a roll of 19.

Long Range Crossbow
A magical hand crossbow capable of shooting much farther and with greater force than usual.

Additional long-range and power damage. It is recommended to use this weapon in your main hand.

Multi-Bolt Crossbow
A magical hand crossbow capable of imbuing arrows shot into it with magic.

There is a high chance that an additional elemental damage will be dealt upon hitting. It also includes a spell container that allows you to launch various magical bolts. Be careful with the teleport bolt; you might get stuck if you shoot it in the wrong direction.

Block Shield
A magical shield capable of reducing damage from attacks.

Provides resistance and includes passive protection.

Repeating Crossbow
This heavy crossbow can be loaded with additional bolts to unleash a devastating volley. Additionally, you can over-crank the mechanism to increase range and damage, but there is a risk of the weapon firing back when over-cranked. The crossbow can be loaded or over-cranked before combat to save time.

Two abilities are activated when you equip this heavy crossbow, each of which, in turn, activates an attack ability.

"Overtighten" is a dexterity check, and if you pass it, you can make an additional powerful shot. However, if you fail, you will ultimately harm yourself.

Reloading fully loads the crossbow but uses an action point to do so. Ideally, you should do this outside of combat as the crossbow remains loaded until it fires or you take a rest. After fully loading, you can release a volley of bolts that hit multiple targets.

All of these items can be found in a suspicious bag located near the stone ruins camp.
See images for additional information.