Craft 3: how to show the Yii Debug Toolbar? I'm using Craft 3 RC and I am logged as an admin. How can I display the Yii debug toolbar on front-end and Control Panel requests? By default, I don't see this toolbar.
There are two checkboxes in your user settings, go to your admin account -> preferences index.php?p=admin/myaccount and check the boxes

This is covered in detail in the Profiling your Website with Craft CMS 3’s Debug Toolbar article