nix/home-manager/modules/thunderbird.nix

{ pkgs, ... }:
{
    programs.thunderbird = {
        enable = true;
        package = pkgs.thunderbird-latest;
        profiles = {
            default = {
                isDefault = true;
                withExternalGnupg = true;
            };
        };

        settings = {
            "mailnews.start_page.enabled" = false;
        };
    };
}