VW Jetta Bora Golf MK4 Beetle Right Front Floor Vent, left this here so people can find it while googling.
My Golf mk4 didn't have a floor vent, so i made one. I don't know if its sizes are anything like the original, since I've never seen one, except on pictures.
Just for fun i also made a 2 colour version, which can be printed as 2 parts that snap together.
Edit: can confirm this also works for Audi A4 (b6).