The encoding for all three file types above (#14.7.6) starts with 5 bytes as follows:
byte 0 = neighbourhood size, k (or the maximum k for a neighbourhood mix).
byte 1,2 = network size, n.
byte 3,4 = i, j for 2d networks (for 1d these bytes are set to null)
The encoding continues as follows, for each successive cell index from 0-(n-1), where k = the maximum neighbourhood:
A. Pseudo-neighbourhood wiring, indexed 0-k, if n<=256, k bytes, if n>256, 2 k bytes
B. Rule: 2k bytes (minimum 1 byte)
Combined wiring-rule scheme: A followed by B.