You might be visiting this page directed via a DuckDB error message, similar to:

INSTALL non_existing;

HTTP Error:
Failed to download extension "non_existing" at URL "http://extensions.duckdb.org/v1.4.0/osx_arm64/non_existing.duckdb_extension.gz" (HTTP 404)

Candidate extensions: "inet", "encodings", "core_functions", "sqlite_scanner", "postgres_scanner"
For more info, visit https://duckdb.org/docs/stable/extensions/troubleshooting?version=v1.4.0&platform=osx_arm64&extension=non_existing

There are multiple scenarios for which an extensions might not be available in a given extension repository at a given time:

• the extension have not been uploaded yet, here some delay after a given release date might be expected. Consider checking the issues at duckdb/duckdb or duckdb/community-extensions, or creating one yourself.
• the extension is available, but in a different repository, try for example INSTALL <name> FROM core; or INSTALL <name> FROM community; or INSTALL <name> FROM core_nightly; (see the Installing Extensions page).
• networking issues, so extension exists at the endpoint but it's not reachable from your local DuckDB. Here you can try visiting the given URL via a browser directly pasting the link from the error message in the search bar.

If you are on a development version of DuckDB, that is any version for which PRAGMA version returns a library_version not starting with a v, then extensions might not be available anymore on the default extension repository.

When in doubt, consider raising an issue on duckdb/duckdb.