Some GNU packages do require copyright assignment to the FSF but anyone is able to do so. Note that the blog post is from 9 years ago. The FSF has made improvements to the process since then [0] and it's now entirely paperless [1]. Some amount of formality will always be needed to keep the copyright transfer formally documented and legally sound.
[0] https://www.fsf.org/blogs/licensing/fsf-to-begin-accepting-scanned -assignments-from-germany [1] https://www.fsf.org/blogs/licensing/fsf-now-offering-paperless-opt ion-for-all-copyright-assignments
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