See wiki

Phifty\App (is a Bundle)
  Phifty\Kernel(

    /* Core service providers */
    "event" => EventServiceProvider,
    "config" => ConfigServiceProvider,

    /* Extra service providers */
    [services] => Array Phifty\ServiceProvider[string]

    "bundles" => BundleServiceProvider(
      Array Phifty\Bundle[string]
    )
  )

1. Create the generated App\ConfigLoader object.
2. Create the generated App\Kernel object
   1. Load the service providers into $kernel
   2. Load the bundles into $kernel
3. Create App\App instance with App($kernel)
4. Call App::boot() method to boot the app.
   1. Call Kernel::boot to boot the service providers and the bundles.
      1. Run ::boot on all the service providers
      2. Run ::boot on all the bundles
   2. Run the App boot code.