NBT Tag formats
From MineTweaker 3
Vanilla tags
Enchantments
Attributes
Attributes are stored in the AttributeModifiers field. For example:
{ AttributeModifiers: [ { AttributeName: "generic.maxHealth", Name: "Heavy Armor", Amount: 180, Operation: 0 } ] }
This kind of attribute would give a player 100 hearts instead of 10.
Sources: