A stl-remix on the standard mk3-extruder-cover, that removes the venturi-hole and instead makes a hole of aproximate size to the side of the heatsink to lower the needed static pressure of the fan to push air through.
This will push less air through the heatsink for a strong fan. For the noctua included in the prusa mk3/mk3s, prusa added the venturi hole to compensate for the low static pressure, giving the fan some head-room, pushing air out through the venturi-hole. The idea was to pull air in when the air passed the hole, but this is not what happens.
So instead of having air escaping on the side, before passing the actual heatsink, we let air pass the heatsink, but lowering the static pressure needed, giving a good flow of air passing the sink, but not through the sink.
This will hopefully pull warm air from the sink with it, and lowering the overall temp of the sink.