Bedrock Edition level format/Block entity format

A block entity is used by Minecraft to store information about a block that can't be stored in the block's block states.

Block Entity

 * The namespaced ID of this block entity.
 * : The X position of the block entity.
 * : The Y position of the block entity.
 * : The Z position of the block entity.
 * : True if this block entity is movable with piston.
 * : (May not exist) The custom name of this block entity.

Banner

 * : The base color of the banner. SeeBanner.
 * : The type of the block entity. 0 is normal banner. 1 is ominous banner‌.
 * : (May not exist) List of all patterns applied to the banner.
 * : An individual pattern.
 * : The pattern id code. SeeBanner.
 * : The base color of the pattern. SeeBanner.

Beacon

 * : The primary effect selected, see Potion effects for IDs. Set to 0 when no effect is selected.
 * : The secondary effect selected, see Potion effects for IDs. Set to 0 when no effect is selected. When set without a primary effect, does nothing. When set to the same as the primary, the effect is given at level 2 (the normally available behavior for 5 effects). When set to a different value than the primary (normally only Regeneration), gives the effect at level 1.

Bed

 * : The data value that determines the color of the half-bed block. When a bed is broken, the color of the block entity at the bed's head becomes the color of the bed item when it drops. SeeBed.

Beehive

 * : True if new bees will be spawned.
 * : (May not exist) Entities currently in the hive.
 * : An entity in the hive.
 * : The entity in the hive. Always  in vanilla game.
 * : The time in ticks until the entity leave the beehive.
 * : The NBT data of the entity in the hive.
 * Actor

Bell

 * : True if it is ringing.
 * : Unknown.
 * : The direction data of this bell.

Brewing stand

 * : The max fuel numder for the fuel bar.
 * : The number of ticks until the potions are finished.
 * : Remaining fuel for the brewing stand.
 * : List of items in brewing stand.
 * : An item in the brewing stand, including the slot tag.
 * : The slot the item is in.
 * ItemStackBase

Campfire and Soul campfire

 * : How long each item has been cooking. is 1, 2, 3, and 4.
 * : (May not exist) List of up to 4 items currently cooking. is 1, 2, 3, and 4.
 * ItemStackBase

Cauldron

 * : If the cauldron contains a potion, this tag stores the ID of that potion. If there is no potion stored, then this tag is set to -1.
 * : If the cauldron contains a potion, this tag stores the type of that potion. 0 is normal, 1 is splash, 2 is lingering. If there is no potion stored, then this tag is set to -1.
 * : (May not exist) This tag exists only if the cauldron stores dyed water; stores a 32-bit ARGB encoded color.
 * : List of items in this container.
 * : An item, including the slot tag.
 * : The inventory slot the item is in.
 * ItemStackBase

Chalkboard

 * : The X postionn of its base.
 * : The Y postionn of its base.
 * : The Z postionn of its base.
 * : The size of this chalkboard.
 * : True if it is on ground.
 * : True if it is on locked.
 * : The Unique ID of its owner.
 * : The text on the chalkboard.

Chemistry tables

 * : (May not exist) Unknown.
 * : (May not exist) Unknown.
 * : (May not exist) Unknown.

Chests

 * : (May not exist) True if this chest is unpair with chest next to it.
 * : (May not exist)
 * : (May not exist) The X position of the chest paired with.
 * : (May not exist) The X position of the chest paired with.
 * : Unknown.
 * : (May not exist) Loot table to be used to fill the chest when it is next opened, or the items are otherwise interacted with.
 * : (May not exist) Seed for generating the loot table. 0 or omitted use a random seed.
 * : List of items in this container.
 * : An item, including the slot tag.
 * : The inventory slot the item is in.
 * ItemStackBase

Command Block

 * : States whether or not the command block is powered by redstone or not.
 * : Allows to activate the command without the requirement of a redstone signal.
 * : Indicates whether a conditional command block had its condition met when last activated. True if not a conditional command block.
 * : Unknown.
 * : Unknown.
 * : Unknown.
 * : (May not exist) Unknown.
 * BaseCommandBlock

Comparator

 * : Represents the strength of the analog signal output of this redstone comparator.

Conduit

 * : The Unique ID of the hostile mob the conduit is currently attacking. If there's no target, defaults to -1.
 * : True if it is active.

Dispenser and Dropper

 * : (May not exist) Loot table to be used to fill the chest when it is next opened, or the items are otherwise interacted with.
 * : (May not exist) Seed for generating the loot table. 0 or omitted use a random seed.
 * : List of items in this container.
 * : An item, including the slot tag.
 * : The inventory slot the item is in.
 * ItemStackBase

Enchanting table

 * : (May not exist) The name of this enchanting table.
 * : The rotation of the book.

End Gateway

 * : Age of the portal, in ticks. This is used to determine when the beam is rendered.
 * : Location entities are teleported to when entering the portal.
 * : X coordinate of target location.
 * : Y coordinate of target location.
 * : Z coordinate of target location.

Flower Pot

 * : (May not exist) The block in the pot.
 * Block

Furnace

 * : Number of ticks left before the current fuel runs out.
 * : Number of ticks the item has been smelting for. The item finishes smelting when this value reaches 200 (10 seconds). Is reset to 0 if BurnTime reaches 0.
 * : The total time that in ticks that the currently used fuel can burn.
 * : The number of experiences it stores.
 * : List of items in this container.
 * : An item in the furnace, including the slot tag.
 * : The inventory slot the item is in.
 * ItemStackBase

Hopper

 * : Time until the next transfer in game ticks, naturally between 1 and 8 or 0 if there is no transfer.
 * : List of items in this container.
 * : An item, including the slot tag.
 * : The inventory slot the item is in.
 * ItemStackBase

Item frame

 * : (May not exist) The rotation of the item in the item frame.
 * : (May not exist) The chance of item dropping when the item frame is broken.
 * : The items in this item frame.
 * ItemStackBase

Jigsaw

 * : The jigsaw block's name. This jigsaw block will be aligned with another structure's jigsaw block which has this value in the target tag.
 * : The jigsaw block's target name. This jigsaw block will be aligned with another structure's jigsaw block which has this value in the name tag.
 * : The jigsaw block's target pool to select a structure from.
 * : The block that this jigsaw block becomes.
 * : The joint option value, either "rollable" or "aligned".

Jukebox

 * : (May not exist) The record item in it.
 * ItemStackBase

Lectern

 * : (May not exist) True if has a book.
 * : (May not exist) The page the book is currently on, starting from 0.
 * : (May not exist) The total pages the book has.
 * : (May not exist) The book item currently on the lectern.
 * ItemStackBase

Lodestone

 * : (May not exist) The id of lodestone.

Mob Spawner

 * BaseMobSpawner

Moving Block

 * : The main layer of moving block represented by this block entity.
 * Block
 * : The extra moving block layer represented by this block entity.
 * Block
 * : The X position of the piston base.
 * : The Y position of the piston base.
 * : The Z position of the piston base.
 * : (May not exist) The block entity stored in this moving block.
 * Block entity

Note Block

 * : The pitch of the note block.

Nether Reactor

 * : Unknown.
 * : Unknown.
 * : Unknown.

Piston

 * : How far the block has been moved. Can be 0.0, 0.5, and 1.0.
 * : Unknown.
 * : Unknown.
 * : Unknown.
 * : True if this piston is sticky.
 * : The list of positions of blocks it should move.
 * : A block's X position.
 * : A block's Y position.
 * : A block's Z position.
 * : Another block's X position.
 * : Another block's Y position.
 * : Another block's Z position.
 * : etc.
 * : The list of positions of blocks it should break.
 * : A block's X position.
 * : A block's Y position.
 * : A block's Z position.
 * : Another block's X position.
 * : Another block's Y position.
 * : Another block's Z position.
 * : etc.

Shulker Box

 * Chest
 * : The facing of this shulker box.

Sign

 * : Unknown.
 * : True if the sign has been dyed with a Glow Ink Sac.
 * : The color that has been used to dye the sign. The default value is "black". One of "white", "orange", "magenta", "light_blue", "yellow", "lime", "pink", "gray", "light_gray", "cyan", "purple", "blue", "brown", "green", "red", or "black".
 * : Unknown.
 * : The text on it.

Skull

 * : The type of this skull.
 * : The rotation of this skull.
 * : True if this dragon head's mouth is moving.
 * : The animation frame of the dragon head's mouth movement.

Structure Block

 * : Whether this structure block is being powered by redstone.
 * : Unknown.
 * : The current redstone mode of this structure block.
 * : X-offset of the structure.
 * : Y-offset of the structure.
 * : Z-offset of the structure.
 * : X-size of the structure.
 * : Y-size of the structure.
 * : Z-size of the structure.
 * : Name of the structure.
 * : Unknown.
 * : Whether entities should be ignored in the structure.
 * : Whether players should be included in the structure.
 * : Whether blocks should be removed in the structure.
 * : Whether to show the structure's bounding box to players in creative mode.
 * : Rotation of the structure.
 * : How the structure is mirrored.
 * : The mode of animation.
 * : Unknown.
 * : How complete the structure is that gets placed.
 * : The seed to use for the structure integrity, 0 means random.