ui/src/main/resources/jcr_root/libs/sling/commons/thumbnails/transformers/greyscale/edit.json

 {
    "jcr:primaryType": "nt:unstructured",
    "sling:resourceType": "sling-cms/components/editor/slingform",
    "button": "No settings required",
    "fields": {
    }
}