TiLDA MK3/NeoPixel
One feature of the Mk3 is a single NeoPixel multi-colour LED adjacent to the red power/charge LED.
Faulty manufacture
Unfortunately, during the original manufacture of the badges the NeoPixel was mounted 180 degrees out of orientation. As originally delivered it will not function, being mounted with the triangular notch facing the outer part of the badge and the chip part of the LED (the brown spot under the transparent pastic) facing the charge LED. The correct position is with the triangular notch facing inward and the chip part facing the "D1" label of the silkscreen.
Correcting the faulty mount
The best solution should be to use soldering tweezers take the LED of, clean the pads turn it and put it on but this is a delicate operation that could probably destroy the LED , the trick is to be quick , to use a fairly high temperature (350-370 degreese) and add some new solder to the pads to increase the heat transfer.
You can possibly use two soldering iron at the same time, one on each side of the LED.
Avoid hot air at all the cost, the badge is packed and you don't really want to risk to blown the charging LED away or even worst, damage the LCD.
Programming the LED
To follow...