An index is a ledger that lists other ledgers. Its list and delist entries hold the ledger id, the address, the owner key and a note.
Anyone can run an index. Usually, the index of a market is also its root.
ledgdex list exchange https://biobot.example --note "knee bone density models"
ledgdex delist exchange LEDGER_ID --reason closedDiscovery reads an index. With --offers, it also reads the open offers and auctions of each listed ledger, with their signed price and terms.
With --json, it writes JSON for programs:
ledgdex discover https://market.example --offers
ledgdex discover https://market.example --offers --jsonIf a listed address serves a different ledger, discovery reports it and does not trust it. Example: Marketplace and Example: Bots choose offers in this way.