saveDomDocument( DOMDocument $doc, string $filename )

Source

File: wp-admin/includes/misc.php

function saveDomDocument( $doc, $filename ) { // phpcs:ignore WordPress.NamingConventions.ValidFunctionName.FunctionNameInvalid
	$config = $doc->saveXML();
	$config = preg_replace( "/([^\r])\n/", "$1\r\n", $config );
	$fp     = fopen( $filename, 'w' );
	fwrite( $fp, $config );
	fclose( $fp );
}