This mod moves the stock UM2+ feeder from the back of the printer to the top. It is suspended on rubber bands and moves with the head while printing. This way the bowden tube can be shortened a lot. It approximates a direct drive setup which can print faster and deal better with flexible filament.
This project is in a very early state. We have thrown it together during the two day long Ultimaker Hackathon. It works (which means it does not burst in flames - yet), but there is still a lot of work to do. Cleaning up the repo first would be a good task...