Google and Yahoo have specified that there needs to be a non-interactive one-click unsubscribe. Mailgun's unsubscribe tracking will only enable the list-unsubscribe feature, but not the non-interactive one click.
Here are the RFC standards for both:
RFC2369 (list-unsubscribe)
RFC8058 (list-unsubscribe-post) (List-Unsubscribe=One-Click).
Can HL add this in the message request header for both Mailgun via the API and SMTP protocol for all others?