>then his own familiarity with the previous LGPL implementation makes the new one almost certainly a derivative of the original.
The "clean room rewrite" is just an extreme way to have a bulletproof shield against litigation. Not doing it that way doesn't automatically make all new code he writes derivative solely because he saw how the code worked previously.
If the clean room re-write was done entirely by Claude, then the result cannot be copyright in the USA, and thus there is no license at all.
And if he was in fact more involved (which he appears to deny) that it's a bit weak to say that someone with huge familiarity with chardet could choose to reimplement chardet without the result being derivative.
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