Yes, it appears that you have created a bridge through libvirt possibly. Honestly, I was never able to make that work, in a useful way. I always create my bridge through the OS itself, which then show up as an option in virt-manager when creating the VM (or can be changed on existing VMs).
I would recommend creating the default network again, the instructions and where to get the data can be found here (from Stackoverflow): Restore default network libvirt
If you create the file just make sure it is named default.xml
Again, if you want a network bridge, I would follow the link for the Arch wiki above to create through the OS.