So, the reason that FSF wants the hold the copyright to the code they distribute is so that they, as the copyright holder, can enforce the license [1]. But why

So, the reason that FSF wants the hold the copyright to the code they distribute is so that they, as the copyright holder, can enforce the license [1]. But why do they need to be the ones enforcing the license on every bit of code they distribute? They could include Magit with Emacs and just declare that they will not be the ones enforcing the license on that part of the code. The main issue I see with such an arrangement is that if Magit was included with Emacs, then conceivably some low-level Magit functions that have more general use could start to find their way into other Emacs code, and other people writing code for Emacs will use those functions in their code. Then the FSF would be in a situation where some of the code that they hold the copyright to depends on code whose copyright they don't hold. To prevent this, I guess they could establish a "contrib" directory in the emacs source for GPL3+-compatible code that is distributed with Emacs but whose copyright is not owned by the FSF. Any GPL3+ code, or really any free software code with a compatible license, could be added in this directory, without copyright assignment, if the Emacs maintainers feel it's worth including with Emacs. Then, they could require that code outside the contrib directory must not depend on code inside it, and that would be a fairly easy rule to enforce. Then they can include Magit and whatever other GPL3+ Emacs packages they want to with Emacs, but they will still have precise knowledge of which parts of the code they hold the copyright to and can enforce the license on (namely, everything outside the contrib directory). Are there any downsides to such an arrangement that I'm missing? Is there something that makes this kind of solution unworkable? Ultimately, I don't see why the FSF doesn't want to distribute any code that they can't enforce the license on. Maintaining copyright on their own code and distributing other people's code aren't mutually exclusive activities. [1]: https://www.gnu.org/licenses/why-assign.en.html https://www.gnu.org/licenses/why-assign.en.html