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

Calculating dependencies ... done!
Dependency resolution took 0.99 s (backtrack: 0/20).

[ebuild  N     ] mail-filter/libopensmtpd-1.0::gentoo  34 KiB
[ebuild  N     ] mail-filter/opensmtpd-filter-dkimsign-0.6-r3::gentoo  23 KiB

Total: 2 packages (2 new), Size of downloads: 57 KiB