Why the groups are a view and not a range

Because the alternative is how an offer list grows without anybody deciding to grow it. Three audiences, three pages, and within a month each page has a thing of its own on it that nobody priced, nobody specified, and nobody can say the state of.

So the grouping is mechanical. data/buyers.yml names offer ids and nothing else; the build joins them to data/offers.yml; and the gate fails the release if a group names an offer that does not exist, if an offer belongs to no group, or if the set of groups changes. A buyer page cannot contain a product, in the same way the eight further offers↗ cannot quietly widen the four that are for sale.