flask-htmx-board1/templates/navbar.html

<nav>
    <div class="nav-wrapper purple darken-3"> 
      <ul id="nav-mobile" class="left ">
        <li> <a  href="/">glavnaya</a> </li>
        
        {% if boards | length > 0 %}  
        {% for board in boards %}  
        <li><a  href="/{{board}}"><span class="new badge red"  data-badge-caption="">{{board}}</span></a> </li>
        {% endfor %} 
        {% endif %} 
        <li>
            <a href="#">Вас закинуло сюда: <span class="new badge blue" data-badge-caption="">{{host_id}}</span></a> 
        </li>
      </ul>
    </div>
</nav>