Ask HN: Source code release upon death

I've always wondered: have any developers ever made arrangements to release source code of their previously closed-source works upon their deaths?

What makes me wonder is that there's a lot of great closed-source software out there, a lot of which has become abandonware (while remaining closed) after their developers move on or disappear. Some closed-source developers may want to keep their work closed while they're alive to control the direction of development or for personal profit -- both reasons which would obviously no longer hold once their author has passed away. Some of them may want to release their source after their deaths, and I'm just wondering if that's ever happened or if anyone has plans to do so.