@strypey @lightweight @os_sci @element Please be correct with your interjections.

Copyright is not owned, as if it was it would never expire - copyright is held by a copyright holder.

The copyright holder cannot infringe their own license, but they cannot revoke say previously licensed GPLv3-or-later and typically what happens with actual free software projects is that the last free version is forked.

Many copyleft projects under say the GPLv3+ often import code from copyright holders under the GPLv3+, which is effective at preventing the project from legally being made proprietary.