This guide holds the filament tube vertical as it enters the top of the extruder. It is a remix of a design by Way2Do. I strongly suggest adding a riser to your printer to provide extra clearance above the extruder.
I had to replace the extruder on my printer. The new one uses a different locking collar for the tube, which sticks up higher than the old one. So I revised the design (V2) to add clearance there. It will need support for printing.
Update: Made the base a bit thicker to hold more securely under the chain attachment. Increased clearance above PTFE locking collar so it doesn't keep it unlocked. Repositioned the brace to avoid possible collision with chain, as mentioned in a remix. (Not an issue on my printer, but I can see how it could be for others.)
The author remixed this model.
Recreated using OpenSCAD, allowing more space for wires coming down from the chain and simplified the overall design slightly.