How to: PHP Internals Reading
*Reading materials related to the PHP internals or performance.*

* [PHP RFCs](https://wiki.php.net/rfc) - The home of PHP RFCs (Request for Comments).
* [Externals](https://externals.io/) - PHP internal discussions.
* [PHP RFC Watch](https://github.com/beberlei/php-rfc-watch) - Watch the latest PHP [RFCs](https://wiki.php.net/rfc).
* [PHP Internals Book](https://www.phpinternalsbook.com/) - An online book about PHP internals, written by three core developers.