Looks like it's released under an MIT license?
(Also as I understand it, it can be hard or impossible to contribute works to the public domain before automatic copyright terms expire in some countries, and that is the justification for CC0.)
(Also as I understand it, it can be hard or impossible to contribute works to the public domain before automatic copyright terms expire in some countries, and that is the justification for CC0.)
Which is true, but not spelt out clearly by breck, and it's kind of annoying for it to be phrased by breck in a way that leaves unclear whether it's merely a semantic nitpick or an actual suggestion that the author should've done something more to waive rights over the work. (I don't think it's the latter; I'm unaware of anything more the OP could do to "fix" this "problem" other than kill himself, and I'm not certain if even that would be sufficient in all jurisdictions.)