Nexus launch day is a cutthroat time when mere moments can make the difference between a speedy shipment and weeks of waiting. While quickly comparing the Nexus 5X and 6P to decide which one to order, many have noticed that the 6P lists an RGB notification LED, but the 5X doesn't. Well, we've confirmed there's an LED on the 5X too. How? We bothered Google VP of Engineering Dave Burke via email. He was kind enough to explain what's going on.
The omission of the LED from the 5X's spec list is a mistake, but it should be corrected soon. The LED is behind the speaker grille on the bottom of the phone. Burke explains that this is a real notification LED, not like that fake LED on the Nexus 6 that only worked with root. Apps can use the LED API to produce any color they want, but the system uses ambient display by default. You can see the LED in the image below, which apparently came from a network test unit.
Photo via Reddit
So if you get the 5X, you'll be able to get LED notifications from apps. You could use something like Light Flow to customize and manage them, but the system favors ambient display. The Nexus phones will also use that LED as a "sign-of-life indicator" in the event something is wrong with the hardware. That's all the Nexus 6's LED was used for, but these are much more capable.