Z:gnu-www-ja-gpl-2.0-faq--a5108d-=3Cb=3E=3Ca href=3D"=23TOCAssignCopyrigh/en

'''Why does the FSF require that contributors to FSF-copyrighted programs assign copyright to the FSF? If I hold copyright on a GPL'ed program, should I do this, too? If so, how?'''