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/msgpack-6.0.0-r1:0/2-c::gentoo  USE="-doc -examples -test" 68 KiB

Total: 1 package (1 new), Size of downloads: 68 KiB