doc/dev/plugins/langswitcher/templates/partials/langswitcher.html.twig

<ul class="langswitcher">
{% set display_format = display_format ?? config.get('plugins.langswitcher.language_display', 'long') %}
{% for language in langswitcher.languages %}

    {% set show_language = true %}
    {% if language == langswitcher.current %}
        {% set lang_url = page.url %}
        {% set active_class = ' active' %}
    {% else %}
        {% set base_lang_url = base_url_simple ~ grav.language.getLanguageURLPrefix(language) %}
        {% set lang_url = base_lang_url ~ langswitcher.page_route ~ page.urlExtension %}
        {% set untranslated_pages_behavior = grav.config.plugins.langswitcher.untranslated_pages_behavior %}
        {% if untranslated_pages_behavior != 'none' %}
            {% set translated_page = langswitcher.translated_pages[language] %}
            {% if (not translated_page) or (not translated_page.published) %}
                {% if untranslated_pages_behavior == 'redirect' %}
                    {% set lang_url = base_lang_url ~ '/' %}
                {% elseif untranslated_pages_behavior == 'hide' %}
                    {% set show_language = false %}
                {% endif %}
            {% endif %}
        {% endif %}
        {% set active_class = '' %}
    {% endif %}

    {% if show_language %}
        <li><a href="{{ lang_url ~ uri.params }}" class="external{{ active_class }}">{% include 'partials/langswitcher-' ~ display_format ~ '.html.twig' %}</a></li>
    {% endif %}

{% endfor %}
</ul>