Dear Maintainer,

In .config/waybar/config I have the network plugin defined with a parameter
  "family": "ipv6"

The man page says this is

This laptop is sitting on a WiFi network (wlp1s0) with only an IPv6 interface so everything is fine by default.
However, as soon as I activate my CLAT interface (wlp1s0-v4, a veth into another namespace) waybar begins showing it instead of the physical interface.

$ ip -br addr show
lo               UNKNOWN        127.0.0.1/8 ::1/128
wlp1s0           UP             2605:a601:a63f:7c02:caa3:e8ff:fe76:98ff/64 fe80::caa3:e8ff:fe76:98ff/64
wlp1s0-v4@if8    UP             192.0.0.1 peer 192.0.0.0/32 fe80::a006:7ff:fe08:fdf4/64

Since this interface only has an IPv4 address I would expect it to be exempt from consideration with this setting.
As soon as the CLAT interface is deleted waybar resumes displaying the stats for wlp1s0.

While I could work around this by setting "interface", I would prefer the autodetect function correctly in the event I were to begin using a USB Ethernet adapter.