htaccess rewriterules cookies

I want to understand how cookies crumble with rewriterules
example below:

RewriteEngine On
RewriteRule ^index\.php - [CO=frontdoor:yes:.example.com:1440:/]
1.
if I resides .htaccess file with the code into the root directory e.g. http://localhost/ (or Applications/AMPPS/www) and access http://localhost/index.php with following code :

<?php
session_start();

echo $_SESSION['frontdoor'];

if(!isset($_COOKIE['frontdoor'])) {
    echo "Cookie named '" . $cookie_name . "' is not set!";
} else {
    echo "Cookie '" . $cookie_name . "' is set!<br>";
    echo "Value is: " . $_COOKIE[$cookie_name];
}
?>

I do not see any cookie named frontdoor ,

2. if I change domain name .example.com with localhost ? though no luck yet ,
I found very little documentation about it over internet , http://httpd.apache.org/docs/2.4/rewrite/flags.html seems a bit too little .