<!DOCTYPE html>
<title>backdrop-filter with opacity:0 under border radius overflow clip should have no effect</title>
<link rel="help" href="https://drafts.fxtf.org/filter-effects-2/#BackdropFilterProperty">
<link rel="match"  href="backdrop-filter-opacity-rounded-clip-ref.html">
<div style="width: 300px; height: 200px; border-radius: 80px; overflow: hidden; position: relative">
  <!-- This should be fully clipped by the outer rounded clip. -->
  <div style="width: 10px; height: 10px; background: cyan"></di