Whether to load the Home Manager session environment, such as home.sessionVariables and home.sessionPath, in env.nu when Nushell starts without it, for example as a login shell. When Home Manager is used as a NixOS or nix-darwin module, the system environment is loaded too.
Enabling this makes Home Manager manage env.nu. Put other environment configuration in programs.nushell.envFile or programs.nushell.extraEnv.