The `channels' field of `operating-system' record

[Nathan Dehnel]

I don't think you're supposed to edit /etc/guix/channels.scm directly,
I think it's generated by guix system reconfigure.
https://gitlab.com/nonguix/nonguix/-/issues/33
I have ~/.config/guix/channels.scm generated by putting
home-channels-service-type in my guix home config.