I installed a fresh Symfony 3 project on a Debian Jessie release (PHP 5.6) with

symfony new Symfony3

I noticed that the Ajax toolbar block is not showing up. I also noticed, that the twig template with the "sf-toolbar-block-ajax" block is not even injected:

I'm not sure if this is related, but the DB icon is also missing, although the DB panel is available:

Michael