OH3 How to deactivate MQTT system broker connection

I’m in the process of migrating from oh 2.5 to oh 3 by doing a new install and moving parts in a step-by-step process.

As before, I installed mosqitto as my primary (and single) mqtt broker. I reusing the mqtt.things file from OH2.5 and installed (via ui) a “MQTT Broker”- and on top of this a “Generic MQTT Thing”-Binding.

I’m not using the “System MQTT Broker”-binding as I assume, that this would only be used to connect to a mosquette broker. (btw, could someone please confirm this?).

Even though I don’t want to use moquette, I get strange error messages in my openhab.log - which I assume are caused of a partial mosquette-configuration in the UI /(Settings–>Other Services–>MQTT system broker connection):

[WARN ] [.MqttBrokerConnectionServiceInstance] - MqttBroker connection configuration faulty: ID segment 'myhostname:s' contains invalid characters. Each segment of the ID must match the pattern [\w-]*.

After removing hostnahme in Settings–>Other Services–>MQTT system broker connection and pressing safe the error message changed to:

[WARN ] [.MqttBrokerConnectionServiceInstance] - MqttBroker connection configuration faulty: host : You need to provide a hostname/IP!

How could I disable mosquette?

Does this link help?

I’m also confused by this. I think it’s a hang-over from OH2, but as the internal (Moquette) broker no longer exists, I don’t know what it’s doing