MQTT embedded broker url

I´m running a bunch of Sonoff´s succesfully in my installation with the mqtt binding and the embedded broker. now I want to add my landroid mower which I don´t get to run.
the landroid mower needs to know the URL for the broker, which I thought is:
“url”: “broker://openhabian:password@”,
when starting the service i receive the following message:

[2019-07-16T12:08:29.077] [INFO] Mqtt - Successfully connected to MQTT Broker!
Mqtt url: undefined

the services is publishing messages but I can`t figure out why they do not arrive in OH.
my mqtt things file:

Bridge mqtt:broker:myBroker [ host=“”, username=“openhabian”, password=“password”, secure=false ]
Thing topic landroid “Landroid” @ “Draussen” {
Type number : batteryLevel “BatteryLevel” [ commandTopic=“landroid/status/batteryLevel” ]

previous to mqtt 2.4 I was able to debug with “mosquitto_sub -h localhost …” to see if messages arrive. how to do that with the embedded mqtt?

Exactly the same way. mosquitto_sub should work with any broker.

A more powerful tool to use is something like MQTT Exploration App