free software, free culture, free hardware
the purpose of this list is to recommend licenses that will ensure maximal freedom for the users of our libraries.
if you want to strengthen the public domain, we recommend the cc0 "license" for any type of work: [[promote-cc0]] this is a waiver of all copyright, which defaults to similar freedom for the user in countries where waiving copyright is not possible.
we especially recommend that you waive copyright on your library pages with cc0.
if you want to support copyleft on your work, we recommend the gnu gpl over the gnu free documentation license. we consider the gnu fdl a non-free license, because it places limits and additional requirements on copies in certain mediums (paper copies.) the gnu gpl is a suitable license for software, and can likely be used in any situation where it is clear what the "source" of the work is.
in other situations, we recommend at least a gpl-compatible license, but will accept works under non-gpl-compatible free software licenses as they are at least free software. the cc0 and x11 licenses are popular, recommended gpl-compatible licenses if copyleft is not one of the criteria you require. note that the fsf generally recommends copyleft licenses over "permissive" choices like cc0 and x11.
we accept that the free culture movement has largely supported the creative commons cc-by and cc-by-sa licenses. these are acceptable free culture licenses, though unlike cc0 they are not compatible with free software or the gpl. we promote these licenses with the note that we think free-software-compatible free culture licenses are better. cc0 is the only creative commons "license" that is gpl-compatible or that can even be used as a free software license.
for the most part, we would discourage creating new licenses. license proliferation divides the free media ecosystem in ways that make works less compatible and less free. an advantage of cc0 is that it is compatible with virtually every other license. in rare instances, a new license is arguably a true necessity, as it likely is with free hardware.
this is not a full list of licenses we will accept for works in our library, but it is a list of all the licenses we recommend adding to your works at this time:
creative commons cc0 1.0 [url]http://creativecommons.org/publicdomain/zero/1.0/[url]
gnu general public license, version 3 [url]http://www.gnu.org/licenses/gpl-3.0.txt[url]
gnu general public license, version 2 [url]http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt[url]
apache 2.0 license [url]http://www.apache.org/licenses/LICENSE-2.0[url]
please note that the apache 2.0 license is compatible with gpl version 3, but not gpl version 2.
x11 derivate license: (based on the curl version of the "mit"[lit]/[lit]x11 license: [url]https://curl.haxx.se/docs/copyright.html[url] -- include the third paragraph if you wish.)
Copyright (c) first year - later year, name(s) of copyright holder(s)
All rights reserved.
Permission to use, copy, modify, and distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
creative commons attribution 4.0 [url]https://creativecommons.org/licenses/by/4.0/[url]
creative commons attribution-sharealike 4.0 [url]https://creativecommons.org/licenses/by-sa/4.0/[url]
note: older versions of these creative commons licenses are acceptable for our library.
gnu lesser general public license, version 2.1 [url]http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt[url]