Added a belt tensioner on the x carriage (remix from https://www.thingiverse.com/thing:1293334), a quick change system for the extruder (remix from https://www.thingiverse.com/thing:3369444), and a 40mm fan holder (remix from https://www.thingiverse.com/thing:3160328)
Smartrapcore from https://www.thingiverse.com/thing:651117
The author hasn't provided the model origin yet.