Multicast Ubuntu Log Question

[mahesh]

Hi,
On an Ubuntu log I came across a section I don't understand. In this Ubuntu log, posted on Pastebin, it says my private laptop is joining Multicast (line 126): https://pastebin.com/2dKhsAGe

(avahi-daemon: Joining mDNS multicast group on interface enp0s25.IPv4 with address 192.168.1.19).

When I googled address 192.168.1.19, I hit a page saying that this address relates to my router, see thumbnail.

However, I do not have a router and I also do not have a server. I just use a commercial modem, no router, and I only use desktop versions of Ubuntu on a private laptop, not a company or work laptop.