No, that’s the short-hand version of checking if the session was set. Instead of having something like
if(isset($_SESSION['firstname'])) {
$firstname = $_SESSION['firstname'];
}
You have something like what Drummin had posted.
It basically means; if $_SESSION[‘firstname’] is set, assign the $firstname variable to it. If it’s empty (notice the single quotes near the end of the equation; single and double quotes with nothing in them means that it is empty), don’t assign the $firstname variable to it.
The ? basically is equivalent to else in the if-else statement.