Exactly as the name suggests, this mount moves the extruder closer to the center of the X-axis, not enough to be perfectly centered as the original Lajbror creation, but enough that X-axis moves no longer have discrepancies in extrusion. It also allows the Z-height limit to be raised to 190mm.

I could not make the Lay Flat Funnel print without gaps in the top surface wherever the print head moved to the right, and I did not want to deal with heat set inserts or the extruder motor being so far away from the Z-carriage, so noticing all builds of the centered extruder showed they are at the same angle, I changed the design to keep the filament path fixed at that angle and moved the extruder slightly closer to the Z-carriage to keep the cable runs shorter. 

Large prints no longer have any extrusion changes as it moves along the X-axis, and it is simpler to assemble with only screws, nuts, and cable ties needed. If the rear z-carriage is replaced with the CM3D's version you can use three M3x25 screws to attach the mount and not need an M3x65 (which I could not find locally). 

Version 2 combines the arm and Z-carriage, further reducing screws needed and increasing overall rigidity. Of the old versions, one has the extruder attached to a pad that is the full width of the body and has 3 holes so an extruder of the Extrusor variant to be mounted. The minimalist version just uses two holes like the original extruder and does not cover the entire extruder body.