https://github.com/whosonfirst/whosonfirst-docs?tab=readme-ov-file#whosonfirst-docs
Unless otherwise noted Who's On First data records are stored in repositories grouped in to one of four namespaces. It would be nice to imagine that we could put all the Who's On First data records in to a single Git repository but that is still not possible to do efficiently yet.
Administrative records, ranging from microhoods to continents, grouped by country (and identified by their two-letter country code). For example all the Who's On First records for Mexico are grouped in to the whosonfirst-data-admin-mx repository.
Postal code records grouped by country (and identified by their two-letter country code). For example all the Who's On First records for Great Britain are grouped in to the whosonfirst-data-postalcode-gb repository.
Venue records grouped by country (and identified by their two-letter country code). For example all the Who's On First records for Canada are grouped in to the whosonfirst-data-venue-ca repository.
Because there are so many venue records for the United States, they have been further subdivided in to per-state groupings identified by their two-letter state code. For example all the Who's On First records for California are grouped in to the whosonfirst-data-venue-us-ca repository.
Who's On First data associated with external data sources. Unless otherwise noted these are grouped by external source, placetype and two-letter country code. For example, Who's On First ancestry data (parent ID and hierarchy) for Foursquare venues in Australia are grouped in to the whosonfirst-external-foursquare-venue-au repository.
The Geocode.earth project provides a number of Who's On First extracts for download in a variety of formats:
https://github.com/whosonfirst