Your quote is exactly an example of what the parent describes, so I think you miss their point. It is at best ambiguous, but to me clearly reads as constructed

Your quote is exactly an example of what the parent describes, so I think you miss their point. It is at best ambiguous, but to me clearly reads as constructed by applying the modifier "open" to the compound noun "source code". Someone talking about red fruit flies hasn't made any reference to red fruit. I make no claim, here, as to the ultimate disposition of the argument, I just don't like points being missed.