When you view the online manual at php.net, it will happily list functions for you to use that will mangle modern text. This is because many PHP functions are old and not aware of newer multi-byte text. So what this script does is to alter each manual page that has old, bad code -- providing a warning in a big yellow box, and giving you a link to the newer, better replacement function.

Such dangerous PHP functions include trim, ucwords, chunk_split, wordwrap, explode, split, strpos, mail, strlen, strtolower, the ereg* functions, and more.