PETG/ABS/equivalent recommended. The design derived from measurements of the broken original part. Since there are hardly any unbroken guards on these machines, the jointing part was considered unfit for purpose and made sturdier here.
Variant 1 replaces the entire unit (1x M5x50 or M5x55 hex socket screw).
Variant 2 only provides a new joint (1x M5x50 or M5x55 hex socket screw + 4x M3x10 & washers), intended to mount the remaining part of the original clear plastic.
Varinat 3 just gluing it back together didn't do it for me.
The author marked this model as their own original creation.