Yes. You have to assign copyright to the FSF in order to contribute anything. This is one reason for its demise. I've done the copyright assignment for both

Yes. You have to assign copyright to the FSF in order to contribute anything. This is one reason for its demise. I've done the copyright assignment for both Autoconf and Automake. It's one reason why there are external macro archives (e.g. Autoconf Archive), when much of this functionality could be in the core projects. Example: Why, in 2021, should you have to rely on external support to do something as trivial as enabling multithreading [ACX_PTHREAD]. It's not even portable to non-pthreads platforms. So much for portability. Contrast with CMake [find_package(Threads); use Threads::Threads]. Compared with CMake, which doesn't require copyright assignment, and anyone can contribute to. It has hundreds of contributors, tons of built-in functionality, and more third-party extensions than Autotools could ever dream of. Copyright assignment is a big part of that, but also so is upstream attitude to third-party contributions. Kitware do this very well. The Autotools maintainers not so much; partly down to their own historical bad choices which prevented change to the internals due to the potential for breaking compatibility.