livecd-rootfs/live-build/ubuntu-server/includes.binary/overlay/etc/netplan/00-installer-config.yaml

# This is the initial network config.
# It can be overwritten by cloud-init or subiquity.
network:
    version: 2
    ethernets:
        all-en:
            match:
                name: "en*"
            dhcp4: true
            optional: true
        all-eth:
            match:
                name: "eth*"
            dhcp4: true
            optional: true