How many bits are used for each word. If 127 skip to reading the next palette version/bits per word (null section). If 0 skip to reading a single Biome ID.
Stored as Blocks Per Word indices, with each unsigned 32-bit integer containing multiple indices, each occupying Bits Per Word bits. The indices are packed and stored in YZX order (Y increments first).
Palette Size
4
The number of Biome palettes stored.
Now loop the next section Palette Size times until you have parsed all biome ids.