we didn’t really have to change your mqtt.cfg
we did it just to make sure that everything is ok and to eliminate a potential cause of problems.
the first line “enforces” the config parameters by first cleaning whatever was configured in the past for the MQTT binding and the applying the correct ones in the file. You can now remove this first line if you want.
the second line just uses the localhost (127.0.0.1) IP address (instead of the local LAN (192.168.0.4) IP)
it’s the same thing (using the localhost IP or the LAN IP) since you are running the broker on the same machine as OH2… Actually… it’s “preferred” to use 127.0.0.1
this is for connecting OH2 MQTT Binding to the Broker
No
you can have multiple items files and only 1 sitemap file and as many rule files as you want
all the items files will be loaded so all the items will be available to OH2