First of all I want to say that I know that this LED flashes slowly when the reset button is pressed twice, this is not the case.
I have searched for information but I have only found that on the MK1000 board this led flashes like this when the LiPo battery was on battery, but I can not find the same answer for the case of the MK1200 or MKR1300 when they are powered by two AA or AAA batteries.
These last two days I left the MK1200 on collecting and sending GPS data but after many hours I noticed that this LED was starting to blink and as I did not know what it meant I turned it off.
Can someone tell me if this is due to the fact that the battery of the batteries was running low and the plate signals this? The first time I saw it, I checked the batteries and they were not completely discharged ...