Formats: bare email · "Name <email>" · "email, Name, key=value;key2=value2" (extra key=value pairs become merge-tag fields)
Recorded per contact as the lawful basis for emailing them — separate from where the row itself came from (paste/CSV). Skipping this leaves consent unverified.
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Leave blank to match all subscribed contacts. Only subscribed contacts are ever included, regardless of tags.