Two reasons for the creation of this thing :
I was concerned about the bending some have experienced with the MK8 original extruder bracket. It was not happening for me (as of yet) but better be prepared for it ...
I wanted a quick & easy access to the nozzle and extruder part, and the bracket was getting in the way.
Note : ABS is strongly recommanded.

You may wonder why there are 2 stl files for this thing, and that's because I ran into a quite unexpected problem.
You're supposed to print extruder_mount_plate_A : it's supposed to be the one with the correct measurements for every mounting holes, but for some reason, when I printed it, the holes were totally off by 4 or 5mm. Strange thing is : knowing that, I ran some calibration process but all return good !
That's why I made extruder_mount_plate_B. This one is supposed to be smaller and normally can't fit but for me ... it does the trick.
So either I have some strange calibration problem going on, either my measurements were off, take your guess ;)