"There is a prevalent practice of licensed copying of declarations and often that is done through what is called open-source licensing" ...(6 minutes later) "sometimes, often the license terms don't include the payment of money, they simply include a requirement like whatever improvements you make have to be given back to the programming community. Have to be made known to other potential programmers. But the copyright holders authority to impose and enforce those licenses obviously depends on the proposition that the code is copyrightable to begin with. And so those licenses would be a pointless gesture otherwise and the very fact that they are offered with such frequency tends to dispel the idea that there is a common understanding in the relevant community that this material is not copyrightable at all."
