As per recent change for security/privacy reasons, form fields would pre-fill lead data only if the token mkt_tok is appended as LP's URL query parameter. Below are the questions -
1. How does the association of lead/person happens with mkt_tok? is this via the AssociateLead JS API?
2. Where is this mkt_tok stored in the Marketo DB against a lead record? I assume its a hashed key and a hidden field in DB for every lead/person (not supposed to be visible for security reasons). Also, do we really care to know about it?
3. Where does the mkt_tok query param get appended to LP URL?