Receive Docker Hub repository webhooks. Use when building a Docker Hub push webhook receiver, because Docker Hub webhooks are UNSIGNED — there is no signature header, no shared secret, no HMAC, no timestamp and no auth option, so signature verification is impossible and must be replaced with a secret URL token plus a re-check against the Docker Hub API. Use when parsing the push_data.tag / push_data.pusher / repository.repo_name payload, when handling the dhi_metadata object on mirrored Docker Hardened Image repositories, when asking why there is no event type field to switch on, or when wondering what to do about the legacy callback_url field.