Drupal Views and Twig templates

Unlike most of Drupal's templates, Views do not provide a file name suggestion for overriding Twig templates. So how do we know exactly what to name our template? View templates can be created in a variety of ways, but the easiest way to remember this is by following this rule:

[base template name]--[view machine name].html.twig

So in the case of our Categories view, will want to create a new Twig template with the name views-view-unformatted--categories.html.twig.

Begin by navigating to the core/modules/view/templates folder and following these remaining steps:

1. Copy views-view-unformatted.html.twig and place it into our theme/octo/templates folder.

2. Rename views-view-unformatted.html.twig to views-view-unformatted--categories.html.twig.

3. Next, we will need to replace the current markup with the following new markup to convert the default <div> to <ul>:

   New markup

   {% if title %}
       <h3>{{ title }}</h3>
   {% endif %}
   
   <ul class="nav nav-list...