The record property this column writes.
OptionalenumLabels for enum columns, so an import accepts the exported label too.
OptionalfieldDrives value coercion (numbers, dates, enums, ...).
OptionalrulesResolved validation rules (registry rules + the column's own), as the form uses.
Header text to match against, and the form label used in error messages.
The column information the importer needs: how to match a header, how to coerce a cell, and how to validate the result.