These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.52 s (backtrack: 0/20).

[ebuild     UD ] net-firewall/iptables-1.8.12:0/1.8.3::gentoo [1.8.13:0/1.8.3::gentoo] USE="-conntrack -netlink -nftables -pcap -static-libs -test -verify-sig" 638 KiB

Total: 1 package (1 downgrade), Size of downloads: 638 KiB