That was not the reason. If so, [L]GPLv2, MIT or several other licenses won't be accepted by OSI.

The issue is CC0 explicitly disclaim any conveyance of patent rights (from the linked faq).

I've been using it for a long time as a "socially acceptable WTFPL" and thought it did, well, exactly the same as WTFPL, let any person in possession of the source do whatever the fuck they want. But apparently with CC0 there are some things they can't do even if the local law allows it?

> Unless expressly stated otherwise, the person who associated a work with this deed makes no warranties about the work, and disclaims liability for all uses of the work, to the fullest extent permitted by applicable law.

If you don't explicitly disclaim warranty then you can get hit by this in Common Law jurisdictions, see [0]

[0]: https://en.wikipedia.org/wiki/Implied_warranty

It's a socially and legally acceptable WTFPL — it includes:

- a "do not sue me" clause for jurisdictions with implied warranty

- a BSD-style permissive license for jurisdictions that do not recognize public ___domain or do not allow directly putting something into it (e.g. Russian law explicitly says that disclaiming authorship is bullshit)