I have read about FSF plugin policy
If modules are designed to run linked together in a shared address space, that almost surely means combining them into one program.
(Emphasis mine). Now there are environments where only one address space exists, such as the real-mode operating system FreeDOS. On FreeDOS you can think of each application/driver as a DOS plugin with that definition (only one address space means everything is in that address space). Can I distribute a proprietary game together with FreeDOS? Can I run it? Or will the distinction in that case be something else (in case of DOS, whether or not it is a TSR program)?