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

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

[ebuild  N     ] net-libs/libnpupnp-6.3.0::gentoo  455 KiB
[ebuild  N     ] net-libs/libupnpp-1.0.3::gentoo  127 KiB

Total: 2 packages (2 new), Size of downloads: 581 KiB