I was about to ask, possibly, the dumbest question ever asked on this forum. But I believe I found the answer (the tiny little light near the ear port/opening).
I still think a good FAQ addition:
If you don't hear/feel the ringtone or vibration, for whatever reason, how do you know afterward that you have a missed call? I got the phone last week, and actually got myself in trouble for not returning important calls.
Since they just hand you the phone, and with no manual, and if you did not have a chance to download the user guide in pdf format.... you may not know about the alert light.
Assuming, one does not know about the alert light yet: Unless you drill in to the call log, or happen to dial *86 for another reason, you have no way of knowing about missed calls/messages.
Nearly all phones, even going back to the 90s, had a some sort of 'missed' icon on the main screen that you have to acknowledge to make it go away. So I think a lot of people expect it. For all I knew (the first time I saw it) the blinking light just indicated that the phone was on...
More research shows there's an app for it on the market, if the blinking light doesn't cut it.