Markup: base_header.twig
<header role="banner">
  <div class="header__top-wrapper">
  </div>
  <div class="header__inner-wrapper">

    {# Manually adding this for Shop developers as our branding block isn't currently a PL element #}
    <div id="block-comicrelief-branding" class="block block-system block-system-branding-block">
      <a href="/" title="Home" rel="home" class="site-logo" tabindex="2">
      </a>
    </div>

  	{% include directory ~ '../../../base/components/navigation/main-nav.twig' %}
  	{% include directory ~ '../../../base/components/meta-icons/meta-icons.twig' %}
    
  </div>
</header>
Source: _shop19-styleguide.scss, line 264