Plugin "Newsfeed"

[polyfragmented]

I'm currently learning how to use SimpleXML and would like a hint on how to save modifications back to a XML file? Let's take this example with (still) hard-coded element content:

Code:

# Load the feed file
    $xml = simplexml_load_file($thp_newsfeed_atom_template_destination);
        
    # Add an entry element as  child
    $entry = $xml->addChild('entry');
        
    # Add child elements to entry
    $entry->addChild('title', 'Page XYZ has been created');
    $entry->addChild('link', 'http://');
    $entry->addChild('id', 'Generate UUID or other id');
    $entry->addChild('updated', 'Insert update time');
    $entry->addChild('summary', 'Repeat title?');

I read up on asXML(), but I don't get it. In example 1 given at php.net, the output includes <?xml version="1.0"?> which is not what I want. Example 2 doesn't have it, but uses XPath. Is example 2 possibly what I want?