The service uses the hostname (libreelec by default) to announce itself. To change it, change the LE hostname.
Posts in this thread indicate that avahi simplifies setup and use of the addon. Do you have any objective reason to want to disable it?
Thanks for the answer!
I was thinking this "TestConnection" in the avahi command is used to announce the service.
No really, just asking about disabling avahi in case someone don't want it.