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

Calculating dependencies ... done!
Dependency resolution took 1.06 s (backtrack: 0/20).

[ebuild  N     ] dev-util/diffball-1.0.1-r2::gentoo  USE="-debug" 89 KiB
[ebuild  N     ] app-portage/emerge-delta-webrsync-3.7.8::gentoo  29 KiB

Total: 2 packages (2 new), Size of downloads: 117 KiB