Comment 14 for bug 1723350

The artful machine is a workstation and has only a wired network interface managed by network-manager that gets configured by a DHCP server on our LAN.
The files you requested are not present or have little or no information:

/etc/network/interfaces
--------------------------------------------------
# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback
--------------------------------------------------

/etc/netplan/01-network-manager-all.yaml
--------------------------------------------------
# Let NetworkManager manage all devices on this system
network:
  version: 2
  renderer: NetworkManager
--------------------------------------------------