Identifiy contact from appended code in bounced/unsubscribed email?

Is there a way to identify a specific contact in Mautic from the appened email in bounced/unsubscribed notices?

That is, if I receive a bounced/unsubscribed email to, is there a way to identify the contact hidden behind “abc123” that this email was sent to?

(I am struggling with bounced emails, am receiving returned/bounced emails from Mailer Daemon with only “” in them (with no other identifier of the contact) and need to at least identify the contacts and mark these as Do not contact manually before finding out the reason and solution of the whole problem.)

Any help would be appreciated, thanks.