chromium/chrome/test/data/prefers-contrast.html

<!DOCTYPE html>
<title>FAIL</title>
<script>
  if (window.matchMedia("(prefers-contrast: more)").matches) {
    document.title = "more";
  } else if (window.matchMedia("(prefers-contrast: less)").matches) {
    document.title = "less";
  } else if (window.matchMedia("(prefers-contrast: no-preference)").matches) {
    document.title = "no-preference";
  } else if (window.matchMedia("(prefers-contrast: custom)").matches) {
    document.title = "custom";
  }
</script>