As per the article here, when sending email campaigns, Hubspot adds certain UTM parameters to links.
One of there is
utm_content, which from the article above is set to "email ID number". I presume that this is some unique identifier for the Contact that clicked the link in the email.
Is there a way to do a reverse-lookup via the API using this "email ID number", and get back a Contact, or at the very least, an email address?