The Fedora Project announced that it changed its classification of CC0 for use in program source code. Free- and Open-Source software developers are not always fond of software licenses but see them more as a necessary evil. When they want to grant almost all rights away, within the limits of the law, they might choose a license such as CC0.
CC0 is a license that aims to waive the maximum amounts of rights possible to “opt-out” of copyright and database protection as far as possible. In some jurisdictions like the US, this “waiving” can be all-encompassing, placing the contents “in the public domain”. In continental European jurisdictions, the author always retains some moral rights.
Until now, CC0 had also been listed as a “good” license for code and content by the Fedora Project, but CC0 is not recommended by the OSI (Open Source Initiative). Richard Fontana now announced that this status will change, and under their new system that distinguishes between “allowed” and “allowed-content” CC0 will no longer be considered a “good” license to use for software, or “allowed-content” only under the new system. This assessment is not surprising as CC0 was never a particular great license to use for software, as it was originally intended for media such as text or images.
The biggest negative aspect mentioned in discussions is CC0’s explicit disavowal of granting any additional rights, such as explicitly not granting patent rights or other intellectual property rights. This disavowl is a problem because in case a patent-holding entity releases software on which they hold patents under CC0, they could later enforce their rights against software projects and authors which incorporated such a CC0-based software. In the announcement post, Fontana describes this change as a matter of principle, as opposed to a change, because it has already caused problems. He describes that until recently, content licenses were required to have the same standard as code licenses, except that they could include a prohibition of modification, and now they can include “no patent license” clauses.
There was in the past also a similar discussion on the debian-legal mailing list, but without an overall conclusion as to the status of CC0 . CC0 is also not listed in the listings of DFSG (Debian Free Software Guidelines) licenses or the list of licenses included in Debian. Overall, it is good that the status of the license was qualified for the Fedora Project, before there was quantifiable harm. For comparison and a sense of scale, as of December 2017, CC0 was used by 195 packages in Debian and on Github, as of August 2022, there are 142k repositories under CC0 – though many at least in the top results seem to be purely media based such as a list of “awesome python resources”.