Most dual licensing companies I've seen use contributor license agreements, not copyright assignments. Based on published materials, FSF's peculiar desire for a

Most dual licensing companies I've seen use contributor license agreements, not copyright assignments. Based on published materials, FSF's peculiar desire for assignments stemmed from some early concerns about court procedure for license enforcement: https://www.gnu.org/licenses/why-assign.html https://www.gnu.org/licenses/why-assign.html Some large companies followed suit. The most interesting is Oracle, which went half way: Their agreement makes Oracle and the developer joint owners of the contribution. https://www.oracle.com/technical-resources/oracle-contributor-agreement.html https://www.oracle.com/technical-resources/oracle-contributo... Rich Hickey later adapted their form for Clojure. I'm sure it's happened elsewhere in the Java community. Opinions on license-versus-assignment this still differ. But other GPL-o-sphere organizations, like Software Freedom Conservancy, have done more public enforcement of late than FSF, without assignments. Especially for the Linux kernel, which has never consolidated copyright ownership in a single organization. https://sfconservancy.org/docs/blank_linux-enforcement-agreement.pdf https://sfconservancy.org/docs/blank_linux-enforcement-agree...