Someone used it for the xxl upgrade since the Z plate dosent have the tension ajuster,im trying to remember and find the link
here you go,it was sarge
I use these on my 3d printer aswell…also you can 3d print them from thingverse
Ultimaker Belt Tensioner v2 by slouce - Thingiverse (printable)
Simple clothespin belt tensioner by mrice - Thingiverse (clothspin instructions)
Customizable Belt Tensioner by nischi - Thingiverse (printable)