NBT
A string or object that defines a named binary tag (NBT) for storing arbitrary data. It consists of key-value pairs (the key being the name of the tag) separated by a comma.
Note
See Minecraft Fandom Wiki: NBT format for more information about named binary tags (NBTs).
Examples
"nbt": "{example: {is_special: 1b, numbers: [100, 3, -56]}}"
This example defines an object NBT that contains an object NBT named example. The example object NBT then contains two NBTs: is_special, which is a byte NBT, and numbers, which is an integer array NBT.
"nbt": {
"example": {
"is_special": 1b,
"numbers": [
100,
3,
-56
]
}
}
This is the same example as above, but formatted as an actual object.