[Question] What does the scaling_position_x/y option do?

I've been using Ueberzug in a program, and I noticed the scaling_position option, but I don't understand what it does. I've tried using it in combination with images of various sizes, and with different scalers, but it doesn't seem to do anything.

Example:

{"scaling_position_x":0.9,"scaling_position_y":0.9,"action":"add","identifier":"test","path":"test.png","x":1,"y":1,"width":15,"height":10,"scaler":"contain"}

[jstkdng]

I believe it sets the origin from which scalers will do their job, with the crop scaler you can see that.