A "basket liner" refers to a material, usually cloth or paper, placed inside a basket to protect it or the items inside from getting dirty or scratched. It acts as a barrier and keeps things safe and neat. Full definition
I use a thin clear plastic basket liner in a crock I use for trash. (theletteredcottage.net)
Moonlight Moss is the first New Zealand company producing sphagnum moss to break into the Canadian market after receiving an order for sphagnum moss basket liners from Hamilton - based Bruans Nursery — which supplies Canada and the United States with its products. (asiapacific.ca)