Why Chunk size 254 exists in Terrain Chunk size options?

Terrain chunk size is 2^n-1, also mentioned in documentation.

public void Setup(int lodCount = 6, int chunkSize = 127)

The size of the chunk (amount of quads per edge for the highest LOD). Must be power of two minus one (eg. 63 or 127).

But in editor there is 254 beside of 255.

It is not even ‘2^n’, it is ‘2^n-2’. Why this strange number exists in options?

I don’t recall why it has bene added but here is a changelog from that addition:

Same commit also has added comment saying “Must be power of two minus one (eg. 63)” :grinning_face_with_smiling_eyes:

Do you think it was mistake?