Theme Updater

I have read this post, and researching relevant articles. I have seen that some have this:

if (empty($transient->checked)) {
   return $transient;
}

1. Is this necessary although I don’t know what it does and why I need it ( the logic ).
2. Do the below is all I need for a theme?

$theme = array(
   'theme' => 'sun',
   'new_version' => '2.0.0',
   'url' => 'https://sun.com/updater.php',
   'package' => 'https://sun.com/releases.php',
   'requires' => '6.0',
   'requires_php' => '8.0.0'
);

Thank you so much in advanced!