I just found this file, now sure if it's related or not.
$: cat /run/NetworkManager/resolv.conf
# Generated by NetworkManager
nameserver ::1
and
$: cat /run/NetworkManager/no-stub-resolv.conf
# Generated by NetworkManager
nameserver ::1
Edit: those are generated from the /etc/resolv.conf
NM generates.
Thought about that too, but I don't have resolvd nor systemd-resolv or systemd-resolve active. Nor do I have avahi running. Interesting isn't it?
Nope :( Neither dnsmasq nor bind are installed. Nothing on port 53 either.