Nikon MH-65 Battery Charger status LED meaning

What does a blinking/static light with the label "CHARGE" mean? "Charging" or "done"?
blinking LED animated GIF on static photo of Nikon MG-65 as background image.
It could be trying to get your attention when you can remove the charged battery.
It could be telling you that it's currently charging because something is happening.
But which is it?

Here's one way to remember: when the LED is*it's also on when there is no battery inserted.

What Nikon says

There does not seem to be a dedicated manual for the battery charger.
The following excerpt is from a random Nikon camera user manual (PDF):

First Steps/Charging the battery

Insert the battery into the battery charger by sliding the battery forward and press down until it locks into place.

No warranty.