nixpkgs-suyu/nixos/modules/system/boot/loader/systemd-boot
Graham Christensen 62652be111
Include date and NixOS version in systemd-boot entries
Grub configs include the NixOS version and date they were built, now
systemd can have fun too:

    version Generation 99 NixOS 17.03.1700.51a83266d1, Linux Kernel 4.9.43, Built on 2017-08-30
    version Generation 100 NixOS 17.03.1700.51a83266d1, Linux Kernel 4.9.43, Built on 2017-08-30
    version Generation 101 NixOS 17.03.1700.51a83266d1, Linux Kernel 4.9.43, Built on 2017-08-31
    version Generation 102 NixOS 17.03.1700.51a83266d1, Linux Kernel 4.9.43, Built on 2017-09-01
    version Generation 103 NixOS 17.03.1700.51a83266d1, Linux Kernel 4.9.43, Built on 2017-09-02
    version Generation 104 NixOS 17.09beta41.1b8c7786ee, Linux Kernel 4.9.46, Built on 2017-09-02
    version Generation 105 NixOS 17.09.git.1b8c778, Linux Kernel 4.9.46, Built on 2017-09-02
2017-09-02 14:28:34 -04:00
..
systemd-boot-builder.py
systemd-boot.nix