Video: LED notifications on Windows Phone
Lumia 730, 735 and 930 have hidden LEDs waiting to be activated
One of the new features expected to be included in the second pre-release version of Windows 10 Technical Preview for Phones is LED notification support.
Leaked screenshots of an upcoming Windows 10 build revealed that Microsoft has enabled LED notifications in Settings -> Notifications + Action Menu and all current smartphones who have such LEDs inside will be able to use these lights for app notifications.
We know that only Nokia Lumia 930, Lumia 735 and Lumia 730 have such LEDs, but more future smartphones may include this functionality once Microsoft brings support for LED notifications. You can watch a video showing the Lumia 735 with LED lights activated:
Source: Geek on Gadgets