When "yes", no attempts are made to bring up or configure matching links, equivalent to when there are no matching network files. Defaults to "no".

  systemd.network = {
    networks = {
      "10-eth-priority" = {
        matchConfig.Name = "enp196s0";
        DHCP = "yes";
        dhcpV4Config.RouteMetric = 1023;
        dhcpV6Config.RouteMetric = 1023;
      };
      "30-enp196s0" = {
        matchConfig.Name ="enp196s0";
        linkConfig.RequiredForOnline = "enslaved";
        networkConfig = {
          Bridge = "br0";
        };
      };
      "40-tap0" = {
        matchConfig.Name ="tap0";
        bridgeConfig = {   };
        linkConfig.RequiredForOnline = "enslaved";
        networkConfig = {
          Bridge = "br0";
        };
      };
      "40-br0" = {
        matchConfig.Name = "br0";
        bridgeConfig = {};
        linkConfig = {
          RequiredForOnline = "carrier";
        };
      };
    };
    netdevs = {
      "20-tap0" = {
       enable = true;
        netdevConfig = {
          Kind = "tap";
          Name = "tap0";
        };
      };
      "20-br0" = {
        enable = true;
        netdevConfig = {
          Kind = "bridge";
          Name = "br0";
        };
      };
    };
  };

tl;dr:

Build system: Meson
Native HTTP/TLS support: The DHCPv4, DHCPv6, and DHCP-DDNS daemons now have native support for API sockets over HTTP and TLS (HTTP), without the need to use the Control Agent (CA).
Classification: Class tags: Option class-tagging allows an option value to be conditionally applied to the response based on the client's class membership. The effect is similar to using an if-block in ISC DHCP to conditionally include options at a given scope. [...] We have added the ability to choose from multiple occurrences of the same option based on class-tagging.
IPv6-only preferred: Kea now supports v6-only-preferred mode, as described in RFC8925, more precisely. [...] Until recently, however, Kea sent back the option and assigned the IPv4 address at the same time; this is now fixed.
Usability: Kea now prints options with binary data in a human-readable form whenever possible
Build system improvements: Kea now compiles properly with Boost 1.87

tl;dr:

• Build system: Meson
• Native HTTP/TLS support: The DHCPv4, DHCPv6, and DHCP-DDNS daemons now have native support for API sockets over HTTP and TLS (HTTP), without the need to use the Control Agent (CA).
• Classification: Class tags: Option class-tagging allows an option value to be conditionally applied to the response based on the client's class membership. The effect is similar to using an if-block in ISC DHCP to conditionally include options at a given scope. [...] We have added the ability to choose from multiple occurrences of the same option based on class-tagging.
• IPv6-only preferred: Kea now supports v6-only-preferred mode, as described in RFC8925, more precisely. [...] Until recently, however, Kea sent back the option and assigned the IPv4 address at the same time; this is now fixed.
• Usability: Kea now prints options with binary data in a human-readable form whenever possible
• Build system improvements: Kea now compiles properly with Boost 1.87