The document discusses the evolution and implementation of Unicode support in PHP 6, emphasizing the importance of consistent character representation across different languages and platforms. It outlines the goals for PHP 6, including the introduction of a native Unicode string type, the use of internal UTF-16 encoding, and the incorporation of the International Components for Unicode (ICU) for robust text processing. Additionally, it highlights the significance of locales and collation in internationalization and localization, and the ongoing development process involving many PHP extensions.