The seed is computed over the mnemonic string itself, and only its ends
were trimmed, so the same words one per line, tab-separated or
double-spaced passed the checksum but gave different keys. The words
are now joined with single spaces before the checksum and the seed. A
test shows each of those three spacings gives the README SSH vector,
and the README section on giving the mnemonic says so.
Model: opus-5-5