clearing Lightbox with Foundation 6

Unfortunately, and at least so far (Foundation 6.2.4) NO there is nothing similar to Clearing in Foundation 6.x. You should install an external plugin, among many that are available.

You can see here the ticket with the Foundation 6 roadmap, Clearing was on the list but it was removed, according to its creators at least temporarily: link

Someone raises an option using Reveal and Orbit (both are Foundation components) as an alternative to Clearing:

<div class="orbit" role="region" aria-label="Favorite Space Pictures" data-orbit data-box-of-bullets="boxOfBullets">
  <ul class="orbit-container">
    <button class="orbit-previous" aria-label="previous"><span class="show-for-sr">Previous Slide</span>&#9664;</button>
    <button class="orbit-next" aria-label="next"><span class="show-for-sr">Next Slide</span>&#9654;</button>
    <li class="is-active orbit-slide text-center" onclick="openOrbitReveal(this)">
      <img src="http://placehold.it/1000x430" alt="" data-zoom-image="http://placehold.it/2000x860">
      <figcaption class="orbit-caption">1. Space, the final frontier.</figcaption>
    </li>
    <li class="orbit-slide text-center" onclick="openOrbitReveal(this)">
      <img src="http://placehold.it/1000x430" alt="" data-zoom-image="http://placehold.it/2000x860">
      <figcaption class="orbit-caption">2. Lets Rocket!</figcaption>
    </li>
    <li class="orbit-slide text-center" onclick="openOrbitReveal(this)">
      <img src="http://placehold.it/1000x430" alt="" data-zoom-image="http://placehold.it/2000x860">
      <figcaption class="orbit-caption">3. Encapsulating</figcaption>
    </li>
    <li class="orbit-slide text-center" onclick="openOrbitReveal(this)">
      <img src="http://placehold.it/1000x430" alt="" data-zoom-image="http://placehold.it/2000x860">
      <figcaption class="orbit-caption">4. Outta This World</figcaption>
    </li>
  </ul>
  <nav class="row boxOfBullets small-up-2 medium-up-4">
    <button class="is-active column" data-slide="0"><div class="callout small"><img src="http://placehold.it/200x86" alt=""></div><span class="show-for-sr">First slide details.</span><span class="show-for-sr">Current Slide</span></button>
   <button class="column" data-slide="1"><div class="callout small"><img src="http://placehold.it/200x86" alt=""></div><span class="show-for-sr">Second slide details.</span></button>
   <button class="column" data-slide="2"><div class="callout small"><img src="http://placehold.it/200x86" alt=""></div><span class="show-for-sr">Third slide details.</span></button>
   <button class="column" data-slide="3"><div class="callout small"><img src="http://placehold.it/200x86" alt=""></div><span class="show-for-sr">Fourth slide details.</span></button>
  </nav>
</div>
<div class="full reveal" id="orbitReveal" data-reveal>
  <button class="close-button" data-close aria-label="Close reveal" type="button">
    <span aria-hidden="true">&times;</span>
  </button>
</div>
<script type="text/javascript">
function openOrbitReveal(that){
  var $orbitClicked = $(that).closest('div[data-orbit]'),
  $orbitPlaceholder = $('<div class="orbit-placeholder"></div>').insertAfter($orbitClicked).css({'height':$orbitClicked.height()}),
  $orbitReveal = $('#orbitReveal'),
  $zoomImages = $orbitClicked.data('zfPlugin').$slides.find('img[data-zoom-image]');

  $zoomImages.each(function(){
    $this = $(this);
    $this.attr('data-original-image',$this.attr('src')).attr('src',$this.attr('data-zoom-image'));
  });
  Foundation.onImagesLoaded($zoomImages, function(){
    $orbitClicked.data('zfPlugin').$slides.css({'max-height':'none'});
    $orbitClicked.data('zfPlugin').$wrapper.css({'height':'auto'});
    console.log($orbitClicked.data('zfPlugin'));
    //$orbitClicked.data('zfPlugin')._prepareForOrbit();
  });

  $orbitReveal.prepend($orbitClicked);
  $orbitReveal.foundation('open');
  $orbitReveal.off('closed.zf.reveal').on('closed.zf.reveal',function(){
    $zoomImages.each(function(){
       $this = $(this);
       $this.attr('src',$this.attr('data-original-image'));
    });
    $orbitPlaceholder.replaceWith($orbitClicked);
  });
}
</script>

The code was taken from: link

Because Zurb has not added native clearing-lightbox, I leave an alternative very easy to implement, explained step by step, greetings!

link