In this example, a folder is copied from one directory to another. The is_dir function is used to check if the source folder exists and is a directory. If it exists, the code creates a new destination folder if it does not already exist by calling the mkdir function. Then, using the scandir function, it scans through all the files in the source folder and copies each file to the destination folder using the copy function. If the file is a directory, it calls the copydir function recursively to copy all subdirectories and files. The package library that provides the PHP Filesystem copy function is the PHP Filesystem Extension (http://php.net/manual/en/book.filesystem.php).