Minecraft wiki entry for Before_1.18, associated text: In Java Edition, the possible shapes of biomes could use only the first 24 bits of the 64-bit world seed, and biome shapes within a world seed could repeat beginning around 229 blocks from 0,0. Biome generation overflowed at 231 blocks from 0,0. However, as biomes were generated in a zoomed out stage, before it was scaled upward, it technically means that biome generation could extend further out during earlier stages of biome generation as the integer overflow point is further out.