Thank you Bjornkusters!
Printed in PETG. Fits nicely.
To (re)place, simply pull the grille of the ventilation-duct-thingy, by pulling the bottom end forward first, then lifting it off.
Unlock the side by lifting the tab, remove the old pin, place the new pin, replace the side, replace the grille.
Do not click this if this is a link PETG
Thingiverse turns "filament brand" and type/color into links, that's why I put "do not click this if this is a link" as filament brand.
You can use any brand PETG filament you can source locally. Mine was probably REAL, 123-3d, or Esun branded. It does not matter.