zulip/templates/zerver/emails/missed_message.txt

{% if show_message_content %}
{% for recipient_block in messages %}
{% for sender_block in recipient_block.senders %}
{% for message_block in sender_block.content %}
{{ message_block.plain }}
{% endfor %}
{% endfor %}
{% endfor %}
{% endif %}

--
{% if mention %}
You are receiving this because you were mentioned in {{ realm_name }}.
{% elif stream_email_notify %}
You are receiving this because you have email notifications enabled for this stream.
{% endif %}

{% if reply_to_zulip  %}
Reply to this email directly, or view it in Zulip:
{{ narrow_url }}
{% else %}
Reply in Zulip:
{{ narrow_url }}

Do not reply to this message. This Zulip server is not configured to accept
incoming emails. Help:
https://zulip.readthedocs.io/en/latest/production/email-gateway.html
{% endif %}

Manage email preferences:
{{ realm_uri }}/#settings/notifications