How do I theme a taxonomy term page? I am working on Drupal 8, trying to get a page template for each vocabulary. I have tried using hook_theme_suggestions_HOOK_alter() to achieve this, but I was not able to do it. 

I tried using Devel with kint(), but no debugging information is shown on my screen. 

How can I add a template suggestion for a vocabulary?
You can suggest a new template file with the following code.

use Drupal\taxonomy\Entity\Term;

function THEME_NAME_theme_suggestions_page_alter(&amp;$suggestions, &amp;$vars) {
  if (\Drupal::routeMatch()-&gt;getRouteName() == 'entity.taxonomy_term.canonical' &amp;&amp; $tid = \Drupal::routeMatch()-&gt;getRawParameter('taxonomy_term')) {
    $term = Term::load($tid);
    $suggestions[] = 'page__taxonomy__' . $term-&gt;getVocabularyId();
  }
}


Then create the file: page--taxonomy--VOCABULARYNAME.html.twig and customise it as you wish.