where as at a minimum you would have to include the relevant API spec which is not on that page.
osquery: status_log_plugin: firehose
--- apiVersion: v1 kind: config spec: osquery: status_log_plugin: firehose
fleetctl apply -f firehose.yml applying fleet config: PATCH /api/v1/fleet/config received status 400 Bad request: json: unknown field "osquery"
should be labelled as helm chart configuration options with probably a mention that there is a helm chart. I also personally found finding this section a bit difficult https://fleetdm.com/docs/using-fleet/configuration-files
Config file format: