This upgrade has been designed to be printed by a resin printer. The fan dock fits a 4020 blower fan (24V to fit the ender 3 stock or v4.2.7 board) with half of its case removed. (Aliexpress link) The fan exhaust is not tuned to perfection and works best without the silicon sock installed on the heat block.
This assembly fits the original extruder back support plate.
You will also need to tap M3x0.5 and M5x0.8 threads in multiple locations.
The author hasn't provided the model origin yet.