Display names for the external ids the matcher references; see matcherReferencesSql. Empty when it references none.
product.name of the rule's route's product.
Composed route display name: ${product.name} · ${product_vendor.name}
for the rule's route. Both columns are NOT NULL and the route join is
INNER, so this is always present.
The next version to take effect, if one is scheduled.
Admin-tier view of a fee rule = identity columns + the columns of the rule's version in effect now (before its first takes effect, its latest).
idis the identity row's external id.