Looks like a wire frame and handle with a metal plate that sits flat at ground level. The wire frame (bit like a coathanger) holds the mouth of the bag open. A

Looks like a wire frame and handle with a metal plate that sits flat at ground level. The wire frame (bit like a coathanger) holds the mouth of the bag open. A plastic bag gets sandwiched in so it's easy to sweep material into the bag, and then remove the bag from the mouth/handle contraption to tie up and dispose of.