When mounting single-row Kallax units to the wall, the cloth/cardboard drawers will hit the square end of the bracket cap.
This ramp/guide is affixed with typical thickness double-sided foam tape and will allow the drawer to easily slide up onto the bracket so the drawer won't stick out of the unit.
Included:
STL
OpenSCAD source included for you to tweak.
PS 3MF project for the included GCODE (MK3/S)
The author hasn't provided the model origin yet.