CC0

   CC0 is a [1]waiver (similar to a [2]license) of [3]copyright, created by
   [4]Creative Commons, that can be used to dedicate one's work to the
   [5]public domain (kind of).

   Unlike a license, a waiver such as this removes (at least effectively) the
   author's copyright; by using CC0 the author willingly gives up his own
   copyright so that the work will no longer be owned by anyone (while a
   license preserves the author's copyright while granting some rights to
   other people). It's therefore the most [6]free and [7]permissive option
   for releasing intellectual works. CC0 is designed in a pretty
   sophisticated way, it also waives "neighboring rights" (e.g. [8]moral
   rights; waving these rights is why we prefer CC0 over other waivers such
   as [9]unlicense), and also contains a fallback license in case waiving
   copyright isn't possible in a certain country. For this CC0 is one of the
   best ways, if not the best, of truly and completely dedicating works to
   public domain world-wide (well, at least in terms of copyright). In this
   world of extremely fucked up [10]intellectual property laws it is not
   enough to state "my work is public domain" -- you need to use something
   like CC0 to achieve legally valid public domain status.

   WATCH OUT: don't confuse CC0 with Creative Commons Public Domain Mark
   (apart from name the symbols are also a bit similar), the latter is not a
   license or waiver, just a tag, i.e. CC0 is used to release something to
   the public domain, while PD mark is used to mark that something is already
   in the public domain (mostly due to being old).

   CC0 is recommended by [11]LRS for both programs and other art -- however
   for programs additional waivers of [12]patents should be added as CC0
   doesn't deal with patents. CC0 is endorsed by the [13]FSF but not [14]OSI
   (who rejected it because it explicitly states that trademarks and patents
   are NOT waived).

   It's nice that CC0 became quite widely used and you can find a lot of
   material under this waiver, but BEWARE, if you find something under CC0,
   do verify it's actually valid, normies often don't know what CC0 means and
   happily post derivative works of proprietary stuff under CC0.

   Some things under CC0 include Librivox audiobooks, [15]Dusk OS,
   [16]Wikidata database, great many things on sites like [17]Wikimedia
   Commons, [18]opengameart (see e.g. Kenney), Blendswap, freesound etc.,
   whole [19]Esolang Wiki, OSdev Wiki (since 2011), [20]Encyclopedia
   Dramatica, [21]LRS software ([22]Anarch, [23]small3dlib, [24]raycastlib,
   [25]SAF, [26]comun) and [27]LRS wiki, [28]books like The Pig and the Box
   (anti [29]DRM child story) or [30]Cost of Freedom, some [31]fonts by
   dotcolon, Lix (libre game), evlisp minimalist [32]Lisp (from book "Lisp
   From Nothing") and many others.

Links:
1. waiver.md
2. license.md
3. copyright.md
4. creative_commons.md
5. public_domain.md
6. free_software.md
7. permissive.md
8. moral_rights.md
9. unlicense.md
10. intellectual_property.md
11. lrs.md
12. patent.md
13. fsf.md
14. osi.md
15. duskos.md
16. wikidata.md
17. wikimedia_commons.md
18. oga.md
19. esolang.md
20. dramatica.md
21. lrs.md
22. anarch.md
23. small3dlib.md
24. raycastlib.md
25. saf.md
26. comun.md
27. lrs_wiki.md
28. books.md
29. drm.md
30. cost_of_freedom.md
31. font.md
32. lisp.md