chromium/third_party/blink/web_tests/external/wpt/css/selectors/first-letter-flag-001.html

<!doctype html>
<meta charset=utf-8>
<title>::first-letter with a Regional-Indicator flag symbol</title>
<meta name="assert" content="::first-letter should apply to symbol characters">
<link rel=help href="https://drafts.csswg.org/css-pseudo-4/#first-letter-pseudo">
<link rel=help href="https://github.com/w3c/csswg-drafts/issues/5099#issuecomment-759612015">
<link rel=match href=first-letter-flag-001-ref.html>
<style>
  p {
    font: 24px/3 serif;
  }
  p::first-letter {
    font-size: 2em;
  }
</style>
<p>&#x1F1EC;&#x1F1E7; UK flag