HTML List render and theming

Example : List

$output = [

  '#theme' => 'item_list',

  '#list_type' => 'ul',

  '#title' => 'My List',

  '#items' => ['Apple', 'Car'],

  '#attributes' => ['class' => 'myclass'],

  '#wrapper_attributes' => ['class' => 'my_list_container'],

];

Preprocessors:

template_preprocess_form(&$vars);

This List use following twig template:

{% if context.list_style %}

  {%- set attributes = attributes.addClass('item-list__' ~ context.list_style) %}

{% endif %}

{% if items or empty %}

  {%- if title is not empty -%}

    <h3>{{ title }}</h3>

  {%- endif -%}

  {%- if items -%}

    <{{ list_type }}{{ attributes }}>

      {%- for item in items -%}

        <li{{ item.attributes }}>{{ item.value }}</li>

      {%- endfor -%}

    </{{ list_type }}>

  {%- else -%}

    {{- empty -}}

  {%- endif -%}

{%- endif %}