[License-review] Output derivatives clause

[Moming Duan]

Hi,


Following the December discussions on distillation, I've updated MG-BY-SA
to address the “Distillation" issue we talked about. Sharing it here in
case it's useful for the conversation.

The main change:
I now distinguish between direct model modifications (Derivative Materials)
and models created by distilling output (Extracted Models). Both need to
stay under MG-BY-SA, but Extracted Models require a notice saying they came
from a model under this license.

Why I think this matters:
We've seen cases like Cursor building Composer 2 on Kimi K2.5 without
disclosure, and the broader distillation concerns from OpenAI/Anthropic.
Lots of Hugging Face datasets don't mention which model generated them,
then get used to train models under different licenses.

I know this doesn't fit the OSD, but it might be useful for model
developers who want to keep derivatives open even when they're created
through extraction.

Curious to hear your thoughts.


Moming Duan




On Dec 29, 2025, at 09:32, Josh Berkus <josh at berkus.org> wrote:

On 12/15/25 9:19 AM, Moming Duan wrote:

That said, I remain focused on this issue and will continue to explore
whether there is a valid case for MG-BY-SA as a proprietary model license
rather than an open source one. My concern is that, in the worst case,
large-scale distillation could reduce the willingness of organizations to
release open models such as Qwen (under Apache-2.0), pushing them instead
toward proprietary service agreements that explicitly prohibit behaviors
like distillation. The reverse is also possible, as some models, like
DeepSeek and Qwen, have relicensed from custom licenses to OSI-approved
licenses.


Please do!  This is a very important question for the OSS licensing of
models.  It may turn out that it's impossible because of the limitations of
copyright on model output, but if so, let's figure that out definitively.

-- 
Josh Berkus
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