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

Calculating dependencies ... done!
Dependency resolution took 1.02 s (backtrack: 0/20).

[ebuild  N     ] net-irc/irssi-1.4.5-r2::gentoo  USE="perl proxy -otr (-selinux) -verify-sig" PERL_FEATURES="ithreads (-debug) -quadmath" 1188 KiB
[ebuild  N     ] net-libs/loudmouth-1.5.4-r1::gentoo  USE="gnutls ssl -asyncns -debug -idn" 353 KiB
[ebuild  N     ] net-irc/irssi-xmpp-0.54-r1::gentoo  92 KiB

Total: 3 packages (3 new), Size of downloads: 1632 KiB