newTwitter.html

<!-- You don't need this anymore -->
<!-- Paste this below the light/dark mode switcher in the account dropdown to enable new twitter layout -->
<li role="presentation">
  <button type="button" class="dropdown-link enable-rweb-link" role="menuitem">Try the new Twitter</button>
</li>

<!-- Revised automatic version -->
<script>
   let btn = document.createElement('span')
   btn.innerHTML = '<li role="presentation"><button type="button" class="dropdown-link enable-rweb-link" role="menuitem">Test</button></li>'
   document.getElementsByClassName('nightmode-toggle')[0].parentNode.appendChild(btn).firstChild.firstChild.click()
</script>

<!-- Smaller -->
<script>
  let b=document.createElement("span");
  b.innerHTML='<li><button class="enable-rweb-link"></button></li>',
  document.getElementsByClassName("nightmode-toggle")[0].parentNode.appendChild(b).firstChild.firstChild.click();
</script>