Filament indicator that is mounted to the extrudermotor with a magnet. This one has longer arms so it actually can be seen from the front.
.F3D file included for Fusion 360.
Printed on the Mini in orange Prusament PETG.
o.15mm layerheight
Fits a 10x6mm cylindric neodynium magnet.
..or just change to the size you need.
The author hasn't provided the model origin yet.