I've been using the Powercore 26800, model A1277, for about three months now, and I love it. It charges my pixel phone extremely fast, on par with the OEM charger (3.8 amp).
I've noticed that when you press the indicator button in a certain way, the indicator lights will flash. Is this a diagnostic feature? The combo is three rapid clicks, the third is held down. Click - click - hold. No matter the battery level, the top two lights will flash for a bit.
I want to know what this is! Nothing about it in the manual.