mDNS repeater and firewall rules

[Steve28]

Can someone help me understand how the mDNS repeater plays into firewall rules? 

I have two networks LAN and IoT.  LAN can access IoT without restriction.  IoT has a Block any to LAN and Block any to This Firewall.  However mDNS repeater is still working as I can see the mDNS advertisements from devices that are on the IoT network.

How is this possible?  I don't see any automatic rules.  Sorry if this is a newbie question..

[fabian]

There are automatic rules but you may not see them in the UI. The pass rule is there for all selected interfaces.

[Steve28]

Even when I dump all rules via command line there are no rules for port 5353 at all....