Here are the possible values:
local: if the payload was read from local mock
remote: if the payload was fetched from the remote backend by forwarding the request
user: if the payload has been created from the user, manually using createPayload
proxy: if the payload has been created from kassette itself, especially for 404 Not found errors (in local mode)
and 502 Bad Gateway errors (when kassette cannot reach the remote server)
Origin of the payload.