eventcally/project/templates/email/newsletter.html

{% extends "email/layout.html" %}
{% block content %}
<p>
    {{ message|safe }}
</p>
<p>
    <a href="{{ url_for('user_notifications', _external=True) }}" target="_blank" rel="noopener noreferrer">{{ _('Notification settings') }}</a>
</p>
{% endblock %}