# If set dns=none and use mullvad vpn, /etc/resolv.conf will have a `search xxx.yyy` line at the end. I don't know why but it seems that line is needed to resolve and connect to xxx.yyy.
# If not set dns=none and not use mullvad vpn, NetworkManager will copy router's DNSes to /etc/resolv.conf and overwirte it which I don't want. There's multiple ways to prevent it: set immutable file attribute, dns=none in NetworkManager.conf, or /etc/resolv.conf.head and /etc/resolvconf/resolv.conf.d/head (need resolvconf?). I only tested dns=none way. The weired thing is in this case `search xxx.yyy` is not needed to reach xxx.yyy
[main]
# https://wiki.archlinux.org/title/NetworkManager#Unmanaged_/etc/resolv.conf
dns=none

[connection]
# needed for mdns to work if not using systemd-resolved
connection.mdns=2