chromium/chrome/test/data/accessibility/input_datalist.html

<!DOCTYPE html>
<html>
<body>
  <input aria-label="input" id="datalist" list="autosuggest" aria-controls="checkbox">
  <datalist id="autosuggest">
    <option value="option1">
    <option value="option2">
    <option value="option3">
  </datalist>

  <div role="checkbox" id="checkbox">checkbox</div>
</body>