Comment by close04

> Are you arguing that MS mistakenly releasing a version of Windows with debug symbols didn't happen or that it constitutes a leak and isn't fair game?

I think he's saying that even having access to leaked or accidentally released originals is not implicit permission to use it freely. Otherwise any piece of software that was ever legitimately released would be fair game, just throw it at a decompiler and profit.

If you're making a clean room design having so many similarities to the original is unlikely to happen accidentally.

Anybody implementing a clean room design should theoretically have no prior knowledge of the original's inner workings. The specs are written by one person, checked to not include any of the original material by a second one, before being passed to a third to be implemented.

From far enough a piece of wire and an isolation transformer do the same thing. The secret sauce is in that isolation, you can't just shunt it and pretend it's the same.