Thank you for your detailed answer. :) I'm gonna ask one more question, please.
> At least this is not the case of Debian. As I previously said, Debian as a > distribution or any other distributions *cannot* have an overall license. > Every distribution is made up of various software. Debian must respect the > original upstream license of each software and must not alter them. If the > upstream license is not reasonable or considered "non-free", Debian would > decide not to include it into Debian's "main" section. As far as I know, > Debian never declared itself to be released "under GPLv2" or any other > licenses. When you are logging in from terminal on Debian devices, the > following greeting information will pop up I was confused Ubuntu cannot have an overall license, because of the license of Ubuntu as below. "Ubuntu operates under the GNU General Public License (GPL) and all of the application software installed by default is free software. In addition, Ubuntu installs some hardware drivers that are available only in binary format, but such packages are clearly marked in the restricted component." (https://en.wikipedia.org/wiki/Ubuntu) But, I can get it clearly now after I know there is no mention of GPL at the Ubuntu's license page. (https://ubuntu.com/licensing) Best regards. 2019년 12월 7일 (토) 오전 4:14, Boyuan Yang <by...@debian.org>님이 작성: > Hi, > > 在 2019-12-06五的 11:06 +0900,JungHwan Kang写道: > > Thank you for your answer. > > > > > 2019. 12. 6. 오전 12:57, Boyuan Yang <by...@debian.org> 작성: > > > > > > Hi, > > > > > > Disclaimer: the canonical answer to license issues should be given by > > > debian- > > > legal mailing list (https://lists.debian.org/debian-legal). There > might be > > > errors in my words below. > > > > > > 在 2019-12-06五的 00:10 +0900,JungHwan Kang写道: > > > > Hi, Debian forks. > > > > I know Debian has GPLv2. > > > > > > My personal understanding is that "Debian" is never ever specifically > > > released > > > under certain license ("GPLv2" or anything else). I have never heard of > > > the > > > saying that "Debian is under GPLv2" or "Debian has GPLv2". Debian is > made > > > up > > > of tens of thousands of individual packages and each package has its > own > > > license recorded in debian/copyright file and you may find that file as > > > /usr/share/doc/<packagename>/copyright when the package is installed on > > > your > > > system. > > > > Is this the license policy for debian below? > > https://en.m.wikipedia.org/wiki/Debian_Free_Software_Guidelines > > The official license policy documentation is published here: > https://www.debian.org/legal/licenses/ . The Debian Free Software > Guidelines > are some high-level guides that are accepted across Debian but they may > not be > the precise description of Debian's license policy. > > > > > > There are many packages having a different license in the Debian > > > > distribution. > > > > How to resolve a conflict between licenses to specify GPLv2? > > > > For instance, GPLv2 & GPLv3 are incompatible. > > > > > > I never heard that GPLv2 license and GPLv3 license are incompatible. > > > > > > The real example of incompatibility should be OpenSSL and GPL ( > > > https://people.gnome.org/~markmc/openssl-and-the-gpl.html) or GPL and > CDDL > > > ( > > > https://lwn.net/Articles/687550/). Debian is aware of those issues and > > > these > > > issues have been taken care of already. > > > > I mean if there is a Linux distribution released under GPLv3, the > > distribution isn’t able to include packages under GPLv2. > > https://images.app.goo.gl/cqzufQ1c7CHP8dNL6 > > > The programs included with the Debian GNU/Linux system are free software; > > the exact distribution terms for each program are described in the > > individual files in /usr/share/doc/*/copyright. > > > > Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent > > permitted by applicable law. > > It only describes the individual licenses of each software and there's > never > an overall license for Debian itself. > > > As other developers said previously (in > https://lists.debian.org/debian-devel/2019/12/msg00034.html ), > "...shipping > two packages whose licenses are incompatible... is never a problem. An > incompatibility can only be triggered when you actually 'combine' the two > packages...". As a result, it's okay for Debian to *ship* both GPL-2-only > packages and GPL-3-only packages. We are talking about shipping only, not > about compiling or linking; the latter case would indeed be a violation of > licenses. > > Aside of that, If you do find any software provided in Debian is using > source > code that are licensed under conflicting licenses (e.g., combining > GPL-2-only > AND GPL-3-only source codes to generate a package) or linking two > binary/libraries that are using conflict licenses (e.g., OpenSSL library > and > original GPL-licensed software, as described in > https://people.gnome.org/~markmc/openssl-and-the-gpl.html) , please file > a bug > against that software in Debian with high severity ("serious"); please also > write to the debian-legal mailing list to report such license violation. > Debian treats those concrete license violations seriously. > > Feel free to let me know if you have other questions. > > -- > Best, > Boyuan Yang > >