So where is the hack? From what I read over there they are still trying to figure it out.
Sorry. It's a Tasker job that enables it. The light is programmed by MOTO to come on only when the Active Display cannot due to low battery. This just enables it at other times. I read the story over on DroidLife and they linked to XDA so I just posted that link.
Moto X Actually Has an Awesome Green Notification Light Hidden Under the Earpiece | Droid Life