$user_id = $_COOKIE['user_id'];This code would retrieve the value of the "user_id" cookie and store it in a variable called "$user_id". The package library used for this function is the PHP core library, which is included with all PHP installations. Overall, the PHP Cookie get function is a useful tool for retrieving information that has been stored in a cookie, and can be used in conjunction with other PHP functions to create dynamic and personalized websites.