http://doc.php.net/downloads/json/php_manual_en.json returns now a 404 instead of a json list with all available PHP functions. This is used in: https://github.com/geany/geany/blob/master/scripts/create_php_tags.py#L19
An alternative could be to scrap all the information from https://www.php.net/manual/en/indexes.functions.php (link found in https://github.com/geany/geany/issues/584#issuecomment-128271692) but it's not ideal.
I'm creating the issue as I also have the same problem in a (Drupal) project that I maintain (https://www.drupal.org/project/api/issues/3489306).