At long last a major Linux distribution has decided to use a sensible structured configuration file format for storing their network interface configuration details! Hallelujah!

Instead of /etc/network/interfaces{,.d/}, cast your little peep-holes upon the relative beauty that is /etc/netplan/ and the nice YAML files that it contains.

Netplan reads network configuration from /etc/netplan/*.yaml which are written by administrators, installers, cloud image instantiations, or other OS deployments. During early boot, Netplan generates backend specific configuration files in /run to hand off control of devices to a particular networking daemon.

Netplan uses NetworkManager on desktop installations, and networkd on server installations to manage the actual network configuration.

On my fresh install, the only file in there was /etc/netplan/50-cloud-init.yaml which was clearly generated by cloud-init.

See https://netplan.io for more information.