This filament guide prevents the filament spool from rocking back and forth during print, which may lead to the issue shown in the last picture (white filament spool).
With a reverse bowden tube, it also evens out the drag to the print head.
Inspired by https://www.printables.com/model/35971-original-prusa-i3-kiss-reverse-bowden-tube .
Print instructions:
The onshape source, if you need to modify hole sizes.
I used the Flashforge Adventurer3 PTFE Bowden Tube.
Based on the original spool holder and the original fs-cover from Prusa, although not really a remix.
The author hasn't provided the model origin yet.