wallabag/app/views/_login.twig

    {% if error %}
        <div class="alert alert-error" >{{ error }}</div>
    {% endif %}
    <form action="{{ path('login') }}" method="post">
        <p><label for="username">{{ 'username'|trans }}: </label><input id="username" type="text" name="_username" value="wallabag"></p>
        <p><label for="password">{{ 'password'|trans }}: </label><input id="password" type="password" name="_password" value="password"></p>
        <p><input type="submit" value="{{ 'login'|trans }}"></p>
    </form>