{% load admin_static admin_list i18n %}
<table>
    <thead>
        <tr>
            <th><div class="text">{% trans "Name" %}</div></th>
            <th><div class="text">{% trans "Default" %}</div></th>
            <th><div class="text">{% trans "Value" %}</div></th>
            <th><div class="text">{% trans "Is modified" %}</div></th>
        </tr>
    </thead>
    {% for item in config_values %}
    <tr class="{% cycle 'row1' 'row2' %}">
        <th>
            {{ item.name }} <div class="help">{{ item.help_text|linebreaksbr }}</div>
        </th>
        <td>
            {{ item.default|linebreaks }}
        </td>
        <td>
            {{ item.form_field.errors }}
            {{ item.form_field }}
        </td>
        <td>
            {% if item.modified %}
                <img src="{% static 'admin/img/icon-yes.'|add:icon_type %}" alt="{{ item.modified }}" />
            {% else %}
                <img src="{% static 'admin/img/icon-no.'|add:icon_type %}" alt="{{ item.modified }}" />
            {% endif %}
        </td>
    </tr>
    {% endfor %}
</table>

{% load admin_static admin_list i18n %}
<table>
    <thead>
        <tr>
            <th><div class="text">{% trans "Name" %}</div></th>
            <th><div class="text">{% trans "Default" %}</div></th>
            <th><div class="text">{% trans "Value" %}</div></th>
            <th><div class="text">{% trans "Is modified" %}</div></th>
            <th><div class="text">{% trans "Reset to default" %}</div></th>
        </tr>
    </thead>
    {% for item in config_values %}
    <tr class="{% cycle 'row1' 'row2' %}">
        <th>
            {{ item.name }} <div class="help">{{ item.help_text|linebreaksbr }}</div>
        </th>
        <td>
            {{ item.default|linebreaks }}
        </td>
        <td>
            {{ item.form_field.errors }}
            {{ item.form_field }}
        </td>
        <td>
            {% if item.modified %}
                <img src="{% static 'admin/img/icon-yes.'|add:icon_type %}" alt="{{ item.modified }}" />
            {% else %}
                <img src="{% static 'admin/img/icon-no.'|add:icon_type %}" alt="{{ item.modified }}" />
            {% endif %}
        </td>
        <td>
             <a href="#" onClick="document.getElementById('{{ item.form_field.auto_id }}').value = '{{ item.default|escapejs }}'; return false;">Reset to default</a>
        </td>
    </tr>
    {% endfor %}
</table>

Add "Reset to default" feature
Add "Reset to default" feature
