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

Calculating dependencies ... done!
Dependency resolution took 0.98 s (backtrack: 0/20).

[ebuild  N     ] dev-libs/utfcpp-4.0.6::gentoo  USE="-test" 34 KiB
[ebuild  N     ] sci-misc/lttoolbox-3.8.2:0/3::gentoo  USE="-test" 154 KiB

Total: 2 packages (2 new), Size of downloads: 188 KiB