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

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

[ebuild  N     ] x11-libs/xcb-util-0.4.1::gentoo  262 KiB
[ebuild  N     ] x11-libs/startup-notification-0.12-r2::gentoo  347 KiB

Total: 2 packages (2 new), Size of downloads: 609 KiB