// writing a string to a file t3lib_div::writeFile('file.txt', 'Hello World!'); // writing an array to a file $data = array('Name' => 'John Doe', 'Age' => 30); t3lib_div::writeFile('data.txt', serialize($data));In the first example, the method is used to write a string "Hello World!" to a file named file.txt. In the second example, an array of data is first serialized using the PHP serialize() function, and the resulting string is then written to a file named data.txt. The t3lib_div class is a part of the TYPO3 CMS core, and it is not available as a separate package or library.