venv/lib/python3.12/site-packages/jupyter_server/templates/error.html

{% extends "page.html" %}

{% block stylesheet %}
{{super()}}
<style type="text/css">
    /* disable initial hide */
    div#header,
    div#site {
        display: block;
    }
</style>
{% endblock %}
{% block site %}

<div class="error">
    {% block h1_error %}
    <h1>{{status_code}} : {{status_message}}</h1>
    {% endblock h1_error %}
    {% block error_detail %}
    {% if message %}
    <p>{% trans %}The error was:{% endtrans %}</p>
    <div class="traceback-wrapper">
        <pre class="traceback">{{message}}</pre>
    </div>
    {% endif %}
    {% endblock error_detail %}
</div>

{% endblock %}

{% block script %}
{% endblock script %}