Every source the ledger is built from, with its live row count.

The list ?provider= and ?exclude_provider= accept. A value that is not here is a 422, never a silently empty page — you can always tell "no jobs match" from "you spelled it wrong".

Only redistributable sources appear. Sources JOA reads but does not republish are named at GET /public/coverage (excluded_sources).

Also served without a key at GET /public/providers, because "which sources is this built from" is a question you should be able to answer before creating an account.