Why extend an MIT licensed model's weights (BiRefNet) and release it under a cc-by-nc-4.0 license?

This pertains to the larger open source licensing discussions that have been happening (as I'm sure you've seen too).

We've released projects under the MIT license before, most notably https://github.com/feyninc/chonkie. While we're not trying to directly monetize on this work, credit goes a long way and helps in other operations.

Recently, attributed usage is shrinking. To be clear, this is not a shrinkage in actual use of our software, just how many people acknowledge that they rely on it.

cc-by-nc is a protection against that. We've been very honest about our work being on top of BiRefNet as we want to extend the original creators the same courtesy. I have no issues if individuals fork/finetune/or otherwise build on top of any open source projects we release, irrespective of license. At minimum, we want acknowledgment if a company chooses to use our software in production.

Btw if you do need a permissively licensed model for this task, there are lots out there, e.g.:

https://github.com/KupynOrest/s3od

https://github.com/Tennine2077/PDFNet

https://github.com/PramaLLC/BEN

Yep, nobody wants to adopt models with this license because it opens legal questions most users, whether professional or non-professional, don't want to muddy their work with.