How do I customize Display Suite? I know that Display Suite change its features due to limitation of PHP script within DS in Drupal 8.

What I want is customize the uploaded file which display something like this:

Code File: sample_file.zip

Into:

Download Code

In which, Download Code is a link the same with the original output as sample_file.zip.

I created a token field in Display Suite and put the following code to no avail:

&lt;a href="[node:field_code_file]"&gt;Download Code&lt;/a&gt;


The output of this is a plain text: 

&lt;a href="/drupal8/sites/default/files/2016-11/sample_file.zip"&gt;Download Code&lt;/a&gt;


Instead of Download Code.

So, how can I link the downloadable File as shown in the image below into something like Download Code with the original link of the file?
The File output (Generic File) is rendered from "file-link.html.twig" template file. To update the Link Text, you can override template_preprocess_file_link() in your theme's themename.theme file. So suppose if my theme name is bartik then function name will be bartik_preprocess_file_link(). Check example below:

use Drupal\Core\Template\Attribute;
use Drupal\file\Entity\File;
use Drupal\Core\Url;

/**
 * Implements hook_preprocess_HOOK() for file-link.html.twig.
 */
function [THEME_NAME]_preprocess_file_link(&amp;$variables) {
  $file = $variables['file'];
  $options = array();

  $file_entity = ($file instanceof File) ? $file : File::load($file-&gt;fid);
  // @todo Wrap in file_url_transform_relative(). This is currently
  // impossible. As a work-around, we currently add the 'url.site' cache context
  // to ensure different file URLs are generated for different sites in a
  // multisite setup, including HTTP and HTTPS versions of the same site.
  // Fix in https://www.drupal.org/node/2646744.
  $url = file_create_url($file_entity-&gt;getFileUri());
  $variables['#cache']['contexts'][] = 'url.site';

  $mime_type = $file-&gt;getMimeType();
  // Set options as per anchor format described at
  // http://microformats.org/wiki/file-format-examples
  $options['attributes']['type'] = $mime_type . '; length=' . $file-&gt;getSize();

  // Use the description as the link text if available.
  if (empty($variables['description'])) {
    // Add new Link text here.
    $link_text = 'Download Code';
  }
  else {
    $link_text = $variables['description'];
    $options['attributes']['title'] = $file_entity-&gt;getFilename();
  }

  // Classes to add to the file field for icons.
  $classes = array(
    'file',
    // Add a specific class for each and every mime type.
    'file--mime-' . strtr($mime_type, array('/' =&gt; '-', '.' =&gt; '-')),
    // Add a more general class for groups of well known MIME types.
    'file--' . file_icon_class($mime_type),
  );

  // Set file classes to the options array.
  $variables['attributes'] = new Attribute($variables['attributes']);
  $variables['attributes']-&gt;addClass($classes);

  $variables['link'] = \Drupal::l($link_text, Url::fromUri($url, $options));
}


Or, you can create a custom field formatter which can be selected on Managed Display Page. as per example provided here, Create a custom field formatter.