<body>
  <h1>Which element is causing the scrollbar to appear?</h1>
  <div class="container1">
    <div class="container2">
      <div class="container3">
        <div class="container4">
          <div class="container5">
            <ul>
              <li>List Item 1</li>
              <li>List Item 2</li>
              <li>List Item 3</li>
              <li>List Item 4</li>
              <li>List Item 5</li>
            </ul>
          </div>
        </div>
      </div>
    </div>
  </div>
</body>
div:nth-of-type(1) {
  background: lightcyan;
}

.container1,
.container2,
.container5 {
  height: 250px;
}

.container3 {
  overflow: auto;
}

.container4 {
  overflow: visible;
}

ul {
  padding: 0;
}

li {
  height: 30px;
  padding: 10px;
  margin: 5px 0;
}

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