If links to PHP files include extension, everything works perfect. This FAQ is only for the case when links to PHP files don’t include extension and you want to use content negotiation to choose PHP files from URL with no extension. In this case, replace the line AddType application/x-httpd-php .php with:
AddHandler php5-script php
AddType text/html php
This solution doesn’t work for Apache 1 as PHP module doesn’t catch php-script.