minecraft-assets/assets/minecraft/textures/gui/sprites/widget/slider_handle.png.mcmeta

{
    "gui": {
        "scaling": {
            "type": "nine_slice",
            "width": 8,
            "height": 20,
            "border": {
                "left": 2,
                "top": 2,
                "right": 2,
                "bottom": 3
            }
        }
    }
}