[microtonal]

In the Nix store (/nix):

    % which cp
    /run/current-system/sw/bin/cp

Each package has its own path in the nix store:

    % readlink $(which cp)
    /nix/store/l96gc2qb8ysnf5hcq1hp5a3r6x905rf4-coreutils-8.31/bin/cp

The current system and previous systems also live in the store (Nix has atomic upgrades/rollbacks). Each system can be seen as a package with symlinks to binaries, man pages, etc. in the store. More information about the motivation behind Nix's approach can be found in Nix Pill 1:

https://nixos.org/nixos/nix-pills/why-you-should-give-it-a-t...