In D7 Webform Civicrm integration, under Additional Options for Civi configuration there is this link
To have this form auto-filled for anonymous users, enable the "Existing Contact" field for Contact 1 and send the following link from CiviMail: https://site.nubay.net/sample-webform?cid1={contact.contact_id}&{contact.checksum}
I do not see the equivalent link for D8 Webforms. Would it be the same link? Should it be in the additional options section?