LevelChunk

Sends a full chunk column: serialized sub-chunks, biome palettes, border blocks and block entity NBT in one payload blob.

level-chunk.bin

struct LevelChunk {
  ChunkPos                                     Pos;
  DimensionType                                DimensionId;
  varuint32                                    SubChunksCount;
  optional byte + varint32                     ClientRequestSubChunkLimit;
  bool                                         CacheEnabled;
  varuint32 [] · SubChunkMetadata[]            CacheMetadata;
  string                                       SerializedChunk;
}

Structure

Field	Type	Description
Pos	ChunkPos
Dimension Id	DimensionType
Sub Chunks Count	varuint32
Client Request Sub Chunk Limit	optional byte + varint32	Presence flag on the wire; value omitted when absent.
Cache Enabled	bool
Cache Metadata	varuint32 count + SubChunkMetadata[]	Length-prefixed sequence.
Serialized Chunk	string

Structure of Serialized Chunk Payload

The uint32-length-prefixed chunk blob, as assembled by PowerNukkitX 3.0.5 for protocol 2193 (LevelDBProvider.requestChunkData).

Field	Type	Description
Sub-chunk Sections	Sub-chunk Section × SubChunksCount	Sections bottom→top starting at the dimension's minimum section Y; only up to the highest non-empty section.
Biome Palettes	Paletted Storage × SubChunksCount	One 16³ biome storage per sent sub-chunk, in the same order. Heightmaps are not sent — the client derives them.
Border Blocks	uint8 count + uint8[]	Education-edition border block column Z-indexes, capped at 255. Vanilla servers write just the 0 count.
Block Entities	network NBT tags	Little-endian network NBT compounds of spawnable block entities. An empty list is a single 0x00 byte (TAG_End).

Structure of Sub-chunk Section

Each serialized sub-chunk starts with its format version and layer count.

Field	Type	Description
Version	uint8	Sub-chunk format version — 9.
Layer Count	uint8	Block storage layers — 2 (second layer is waterlogging).
Y	int8	Sub-chunk Y index relative to the dimension's minimum section.
Block Layer 0	Paletted Storage	Block states; palette entries are network block state hashes when StartGame set Block Network Ids Are Hashes.
Block Layer 1	Paletted Storage	Liquid layer (waterlogged blocks).

Structure of Paletted Storage (network)

Shared encoding for block and biome data: a bit-packed word array plus a palette of runtime values.

Field	Type	Description
Header	uint8	(bits << 1) \| 1 for network format. bits ∈ {1,2,3,4,5,6,8,16}; 0 = uniform storage. A header of 0xFF means "same palette as the previous storage" and nothing else follows.
Words	int32 (LE) × ⌈4096·bits/32⌉	Bit-packed palette indices for the 16³ cells; absent for uniform storage.
Palette Size	varint32	Number of palette entries; omitted for uniform storage.
Palette	varint32 × size	Runtime values — block state hashes (blocks) or biome ids (biomes).

Notes

The payload is a uint32-length-prefixed blob — the full layout is in the tables below.
The limited sub-chunk request system: when Sub Chunks Count is 0xFFFFFFFE/0xFFFFFFFF the client pulls missing sub-chunks via SubChunkRequest instead of receiving full columns.
Cache Enabled pairs with ClientCacheBlobStatus/ClientCacheMissResponse to dedupe unchanged chunks by blob hash.
Sub Chunks Count counts only up to the highest non-empty section; biome palettes are sent for exactly those sections.