https://github.com/NixOS/nix/pulls?q=is%3Apr+label%3Aca-derivations+is%3Aclosed

2021
https://www.tweag.io/blog/2021-12-02-nix-cas-4/
2020
https://www.tweag.io/blog/2020-11-18-nix-cas-self-references/
https://www.tweag.io/blog/2020-09-10-nix-cas/