chromium/third_party/blink/web_tests/fast/css/first-letter-wbr-first-character.html

<!DOCTYPE html>
<style>
div { color: green; font-size: 40px; }
div:first-letter { color: red; font-size: 40px; }
</style>

<p>This test is successful if the 'T' below is green.</p>
<div><wbr>T</div>