Remove "Hacker's Guide" from the PHP manual?

Hi everybody! In my opinion, we should remove the internals2 book[1] (“PHP at the Core: A Hacker's Guide”) from the PHP manual, since it is still not basically up-to-date with PHP 7 (and nobody seems to be working on that). Actually, it even states[2]: | The documentation in this section is current as of PHP 5.3.3, […] And there is at least one bug report[3] about this. Instead of investing a lot of time to update the book, I think it is more sensible to replace it with a single page which links to external documentation, such as <http://www.phpinternalsbook.com/>, and to help improving and keeping the external docs up to date, if appropriate. Thoughts? [1] <http://www.php.net/manual/en/internals2.php> [2] <http://www.php.net/manual/en/internals2.preface.php> [3] <https://bugs.php.net/bug.php?id=73014> -- Christoph M. Becker