Codebase Browser
chromium
Go to App

chromium/third_party/blink/web_tests/external/wpt/mathml/crashtests/operator-and-first-letter.html 

<!DOCTYPE html>
<style>
  p::first-letter { --panel-arrowcontent-color:-moz-FieldText; }
</style>
<p>
  <math display="block">
    <mo>&#x222B;</mo>
  </math>
</p>