Toward a "modern" Emacs

In practice, it's "open source" for the vendor/developer, but "closed source" for the downstream end-user, because the former isn't required to pass along the same rights (ie the source code) to the latter.

In the real world, I've been forced to use a lot of proprietary software that is built on top of "open source" codebases. This includes multiple android devices and several variations of LLVM. After all, _I_ don't have the source code to what is actually running.