Example 10. of man page of systemd.network(5) shows:
```
Example 10. MacVTap
This brings up a network interface "macvtap-test" and attaches it to "enp0s25".
# /usr/lib/systemd/network/25-macvtap.network
[Match]
Name=enp0s25
[Network]
MACVTAP=macvtap-test
```
Which is a MACVTAP example and is currently unsupported in NixOS.
This is useful for people using "modern" technologies with virtual machines.