third_party/WebKit/LayoutTests/css3/filters/backdrop-filter-svg.html

<svg width="200" height="200">
    <rect width="50" height="50" fill="blue"></rect>
    <rect x="20" y="20" width="50" height="50" fill="green" opacity="0.5" style="backdrop-filter: blur(10px);"></rect>
</svg>