[Mailman-Developers] URLs in notification messages

Hey there!

I have a question about emails generated by Mailman3. This is an example of a "message held" notification ("your message awaits moderator approval"). According to the template, Mailman inserts a cancel link at the end of the email:

If you would like to cancel this posting, please visit the following URL: https://example.com/confirm/test@example.com/longhash

I wonder where this link is supposed to lead. I did not find such an endpoint in Postorius, and the Mailman REST API is not public anyway. Am I missing something?

Thanks! Aurélien