How to work with Session correctly?

Question

PHP

Question about session_abort() function ..
Why can I access data in session array after calling this method?

print_r($_SESSION);

echo '<br>';
echo session_start();

try {
    if(Login::getInstance()->logger($_POST)){
     echo $_SESSION['email'] = $_POST['email'].' Logged in!';
    }
}catch (LoginFailed $login){
    session_abort();
   echo $login->getMessage();
}catch (ValidationError $error){
    session_abort();
    $errors = $error->getErrors();
    foreach ($errors as $key => $value){
        if (is_array($value)){
            foreach ($value as $inner_value){
                echo '<br>';
                echo 'Valid email example => '.$inner_value;
            }
            return;
        }
        echo $error->getMessage().strtoupper($key).' => '.$value;
    }
}catch (DatabaseConnectionError $error){
    session_abort();
    echo $error->getMessage();
}

echo '<br>';
print_r($_SESSION);
echo '<br>';
var_dump(session_status()== PHP_SESSION_ACTIVE);

Answer 1

echo '<br>';
echo session_start();

what are these structures?
as far as remembering, it is desirable to always put the first command simply

session_start();

and before it there should be no conclusions