Product Showcase - Interior

As you can see, the 570X is equipped with mounting trays in the back as well as a  power supply compartment. To the left you can "hang" two HDDs, to the right you can see mounts for two SSDs and as well observe a LED controller. Very clean looks BTW, but let's zoom in a little.
 

So the device to the left basically is a LED hub, it has the three LEDs from the fans connected to it. There's actually six connectors, so you could add another three SP120 RGB fans if you like to do so.
 

 
Here you can see that HUB a bit better. This is just the HUB though, basically you can see it as a splitter primary for the lighting. The wire leads out to a controller. 
  

 
Here is that controller, which allows for the color changes and LED animations. From here on there is a wire leading to the front IO panel, where buttons are located to control this setup. So LED RGB control is managed are the front IO.