Which sources are indexed?
Listings are collected from public listing sites and normalised into a single shape, so one search covers catalogues that describe the same thing in different words. Every listing keeps a link back to its original source.
Normalisation is the point: one site's "estate", another's "wagon" and a third's "touring" become the same searchable concept. We do not republish source pages for search engines to index — the original listing is the canonical version and the authority on price and availability, and we link to it rather than compete with it.