Jonathan Riddell wrote moments ago on the KDE blog about no license being needed for Kubuntu-derived Linux distributions. Riddell noted, "Early last year the Linux Mint developer told me he had been contacted by Canonical's community manager to tell him he needed to licence his use of the packages he used from Ubuntu...Time passed, at some point Canonical changed their licence policy to be called an Intellectual property rights policy and be much more vague about any licences needed for binary packages. Now the community council have put out a Statement on Canonical Package Licensing which is also extremely vague and generally apologetic for Canonical doing this."
While Canonical may have a different feeling for Ubuntu derivatives, Jonathan Riddell said about Kubuntu, "let me say clearly, no licence is needed to make a derivative distribution of Kubuntu. All you need to do is remove obvious uses of the Kubuntu trademark. Any suggestion that somehow compiling the packages causes Canonical to own extra copyrights is nonsense. Any suggestion that there are unspecified trademarks that need a licence is untrue. Any suggestion that the version number needs a trademark licence is just clutching at straws."