It fixes attachments points from 3 legendary barrels:
Big Kahuna Barrel
Astatoz Barrel
Anarcho Barrel
Regarding the Anarcho barrel.
Small warning on this one, you need to unequip and reequip the barrel on your judge to fix it IF you already have a judge equipped with it.
If you uninstall the mod, Anarcho barrel would be removed from your judges.
Regarding the use of Add-On Legendary Attachments
The addon barrel for the Anarcho is still considered as Barrel since it use the same data as the original. I'm getting in touch with fragtane to see if you can work this out and create a compatibility with my mod.