For one thing, I don't think they think they have a silver bullet here. I think they want
some financial support and if
some users of the project pay the fee that will be
some success.
To the specifics, it's not a software license fee -- they aren't selling access to the software. It's a "maintenance fee", to fund the project. So the license of the code isn't a problem, you can (still) choose to license that under whatever terms are available.
From their FAQ[0]:
> Q: What if I don’t want to pay the Maintenance Fee?
> That’s fine. You can download the project’s source code and follow the Open Source license for the software.
> Do not download releases. Do not reference packages via a package manager. Do not use anything other than the source code released under the Open Source license.
> Also, if you choose to not pay the Maintenance Fee, but find yourself returning to check on the status of issues or review answers to questions others ask, you are still using the project and should pay the Maintenance Fee.
[0] https://opensourcemaintenancefee.org/consumers/faq/
To the specifics, it's not a software license fee -- they aren't selling access to the software. It's a "maintenance fee", to fund the project. So the license of the code isn't a problem, you can (still) choose to license that under whatever terms are available.
From their FAQ[0]:
> Q: What if I don’t want to pay the Maintenance Fee?
> That’s fine. You can download the project’s source code and follow the Open Source license for the software.
> Do not download releases. Do not reference packages via a package manager. Do not use anything other than the source code released under the Open Source license.
> Also, if you choose to not pay the Maintenance Fee, but find yourself returning to check on the status of issues or review answers to questions others ask, you are still using the project and should pay the Maintenance Fee.
[0] https://opensourcemaintenancefee.org/consumers/faq/