Ordering of authentication sequences

I have a question on the ordering of authentication sequences, as I find the documentation a little unclear.

Given the setup below
image

Is the execution order 0, 1, 2 or 2,1,0 or is the it actual listing order as they appear in the config.yml file?

Many thanks.

The execution order is from lower to higher (0, 1,2).
In config.yml the value doesn’t depend of the order in which they appear, but they depends on order parameter in the authc block

 kerberos_auth_domain:
        http_enabled: false
        transport_enabled: false
        order: 6
        http_authenticator:
          type: kerberos
          challenge: true
          config:
            # If true a lot of kerberos/security related debugging output will be logged to standard out
            krb_debug: false
            # If true then the realm will be stripped from the user name
            strip_realm_from_principal: true
        authentication_backend:
          type: noop

Many thanks for the clarification. Will.