what <ipv6allow> does? && missing IPv4 gateway after update

[plyn]

Hi there,
I have opened config.xml and am wondering what this actually means:
<opnsense>
   <system>
   ...
       <ipv6allow>1</ipv6allow>
   ...

Obviously it will allow ipv6. But I'm really not sure where to find it in the gui or what it actually does.

I'm asking because I recently ran into this problem:
https://forum.opnsense.org/index.php?topic=38631.msg189107#msg189107
(tl;dr Default gateway for IPv4 disappeared after upgrade)

Also in System: Gateways: Configuration this appeared:
https://imgur.com/a/iMTJIwu
and could not be deleted for some reason. After clicking on bin icon, it just did nothing.

After a week it happened again randomly after a reboot.

So I decided to compare my config.xml with the default one.
One of the many differences in my config was<ipv6allow>1</ipv6allow> and I am not sure if this could be related to the problem.

I also find this overflow in my config:
 <gateways>
    <gateway_item/>
  </gateways>
So I deleted it. And the undeletable undefined gateway disappeared.

Not sure if my problems are solved now or if it could happen again. Also not sure if its a bug in opnsense 24.1 or if I am just dumb bfu.

Thanks everyone for any advice!

[zan]

   ...
       <ipv6allow>1</ipv6allow>
   ...

Obviously it will allow ipv6. But I'm really not sure where to find it in the gui or what it actually does.

This will enable pf to process IPv6 traffic.
Related setting in GUI is Firewall>Settings>Advanced>Allow IPv6.