I wrote the first bulleted link, should have included a gigantic caveat: CC0-1.0 expressly excludes any patent grant. That makes it dangerous for non-trivial so

I wrote the first bulleted link, should have included a gigantic caveat: CC0-1.0 expressly excludes any patent grant. That makes it dangerous for non-trivial software, is why CC eventually withdrew it from consideration for OSI approval, and why it isn't highlighted on choosealicense.com which is primarily about software -- though it is mentioned on https://choosealicense.com/non-software/ https://choosealicense.com/non-software/ I think the reason choosealicense.com originally featured Unlicense relative to other unconditional license options is that one of the creators of the Unlicense (bhuga) was also one of the creators of choosealicense.com. But previous paragraph is why it's still there.