This discussion does appear to be fruitless. I will say it again, it is not my intention to tell you under what terms you should license MakeHuman under. I am merely trying to tell you that the current license is not as clear as you think it is, and that CC0 is, under most circumstances, not a license and can only be applied to a work not a copy of a work.
EDIT: After further research I found the following sentences to be incorrect, in several significant jurisdictions, including Germany, the CC0 waiver is not valid and the fallback license takes effect. Nonetheless, the end effect is the same, CC0 creates a public license to the WORK, not a specific copy of the work.
If you live in Europe or North America, with the possible exception of Belgium, the law in your jurisdiction allows you to place your work in the public domain and the effect of applying CC0 is to place your work in the public domain.[/s] The CC0 license was crafted to be applicable in any jurisdiction in the world and to take into account that some (minor) jurisdictions do no allow you to place your work in the public domain. That does not apply in this case.
And even if it did it would make no legal difference to the rights of any of the parties.
Here's what the CC wiki page Rob linked to says:
Copyright and other laws throughout the world automatically extend copyright protection to works of authorship and databases, whether the author or creator wants those rights or not. CC0 gives those who want to give up those rights a way to do so, to the fullest extent allowed by law. Once the creator or a subsequent owner of a work applies CC0 to a work, the work is no longer his or hers in any meaningful sense under copyright law. Anyone can then use the work in any way and for any purpose, including commercial purposes, subject to other laws and the rights others may have in the work or how the work is used. Think of CC0 as the "no rights reserved" option.
...
How does it work?
A person using CC0 (called the “affirmer” in the legal code) dedicates a work to the public domain by waiving all of his or her copyright and neighboring and related rights, if any, in a work, to the fullest extent permitted by law
From the CC CC0 page:
And while no tool, not even CC0, can guarantee a complete relinquishment of all copyright and database rights in every jurisdiction, we believe it provides the best and most complete alternative for contributing a work
to the public domain given the many complex and diverse copyright and database systems around the world.
https://creativecommons.org/share-your- ... omain/cc0/
From the CC human-readable CC0 page:
The person who associated a work with this deed has dedicated the work to the public domain by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
From the CC legal-text:
2. Waiver. To the greatest extent permitted by, but not in contravention of, applicable law, Affirmer hereby overtly, fully, permanently, irrevocably and unconditionally waives, abandons, and surrenders all of Affirmer's Copyright and Related Rights and associated claims and causes of action, whether now known or unknown (including existing as well as future claims and causes of action), in the Work (i) in all territories worldwide, (ii) for the maximum duration provided by applicable law or treaty (including future time extensions), (iii) in any current or future medium and for any number of copies, and (iv) for any purpose whatsoever, including without limitation commercial, advertising or promotional purposes (the "Waiver"). Affirmer makes the Waiver for the benefit of each member of the public at large and to the detriment of Affirmer's heirs and successors, fully intending that such Waiver shall not be subject to revocation, rescission, cancellation, termination, or any other legal or equitable action to disrupt the quiet enjoyment of the Work by the public as contemplated by Affirmer's express Statement of Purpose.
It was even explicitly confirmed to me by the CC General Counsel that CC0 applies to a work and not a copy.
Now, if you can read all that and still think that CC0 does not place a work in the public domain then there truly is no point in talking further.
I have nothing against CC0, I would be delighted if MH were to explicitly apply CC0 to the various assets that may be exported. Then everyone would know where they stood.
My first point is that the idea that an asset can be CC0 if exported by an unmodified version of MH but AGPL if exported from a modified version of MH, is legally incorrect. Once CC0 is applied to a work you can no longer use copyright to enforce any other license on any copy of it. So, all that including the language about unmodified official versions does in confuse matters.
My second point is that it isn't at all clear what the effect of the CC0 exception is.
As a special and limited exception, the copyright holders of the MakeHuman assets grants the option to use CC0 1.0 Universal as published by the Creative Commons, either version 1.0 of the License, or (at your option) any later version, as a license for the MakeHuman characters exported under the conditions that...
Does "grants the option to use CC0" mean that MH will apply the CC0, or that the user will apply CC0? Which one makes a big difference. If MH applies the CC0 then all copies of the asset are covered and MH no longer has any copyright rights over the assets or any copies thereof. If you read it as "grants the option for the user to use CC0" then the user uses the option they have given up any copyright rights to the export but MH's copyright rights remain unaffected.
From the CC wiki:
I don't think correct legal interpretation is at all clear, and if I were placing a bet on how a judge would read it I would have to go with the "grants the user the option for the user to use CC0". The upside of that would be that MH would not yet have given up its rights to the assets. The downside is that the CC0 exception is effectively meaningless, the bundled assets are still AGPL.
While I think it would be to MH's benefit to have clear license terms it is clear to me that there is no interest in fixing the license so that's about all that needs to be said here.
P.S. Thank you wolgade for recognizing that I don't have bad intentions. Sorry to everyone I have caused irritation, in my own mind my intentions were good.