Also MIT-0. Note that CC0 is not an OSI-approved license. It was withdrawn because the OSI didn't like that it explicitly does not grant patent rights to use the software.
When I read your comment I initially thought "that can't be right".
And then I found [1]:
> CC0 was not explicitly rejected, but the License Review Committee was unable to reach consensus that it should be approved, and Creative Commons eventually withdrew the application. The most serious of the concerns raised had to do with the effects of clause 4(a), which reads: "No ... patent rights held by Affirmer are waived, abandoned, surrendered, licensed or otherwise affected by this document.". While many open source licenses simply do not mention patents, it is exceedingly rare for open source licenses to explicitly disclaim any conveyance of patent rights, and the Committee felt that approving such a license would set a dangerous precedent, and possibly even weaken patent infringement defenses available to users of software released under CC0.
For the record, the FSF also recommends against using CC0 for software for the exact same reason [2].
I was surprised because my first impression was that this clause does not legally do anything more, anything less than a license that does not explicitly grants the rights to use the related software patents anyway. But I can imagine that without an explicit mention, a judge could still decide that a user receiving a program could reasonably feel allowed to use the related patents from its authors.
Anyway, CC0 should not be used or software indeed I guess, given the vagueness around it.
>I was surprised because my first impression was that this clause does not legally do anything more, anything less than a license that does not explicitly grants the rights to use the related software patents anyway. But I can imagine that without an explicit mention, a judge could still decide that a user receiving a program could reasonably feel allowed to use the related patents from its authors.
