"All rights reserved" no longer means anything anymore. In the past, you had to state that you want to reserve copyright, but now this has become the default ev

"All rights reserved" no longer means anything anymore. In the past, you had to state that you want to reserve copyright, but now this has become the default even if you say nothing. Either way, this does not conflict with GPLv3; if the author decides to reserve all rights, and then use their reserved right to license the work under a certain license like GPLv3, that is totally fine. Notably, the phrase "All rights reserved" does not recapture any rights that you don't have. It is the same logic under which you're allowed to license your own GPLv3 code under a proprietary, non-FOSS license, but that doesn't revoke the GPLv3 license itself.