title: What does PHP's Phar::mapPhar() method do?
body: <p>I'm considering creating a phar stub to use in a PHP CLI application.</p>
  
  <p>The documentation for the <a href="http://uk.php.net/manual/phar.mapphar.php" rel="nofollow">Phar::mapPhar</a> method says it "Reads the currently executed file (a phar) and registers its manifest".</p>
  
  <p>Could you explain what it means to 'register its manifest' and also indicate what would happen if it were called with no arguments. Why would I want to register a manifest? What benefits do i get from adding this call to my phar stub.</p>