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

Calculating dependencies ... done!
Dependency resolution took 1.02 s (backtrack: 0/20).

[ebuild  N     ] media-sound/shntool-3.0.10_p1::gentoo  216 KiB
[ebuild  N     ] media-libs/flac-1.5.0:0/11-14::gentoo  USE="cxx -debug -ogg -static-libs" CPU_FLAGS_X86="avx avx2" 1054 KiB
[ebuild  N     ] media-sound/shnflacverify-0.3-r1::gentoo  12 KiB

Total: 3 packages (3 new), Size of downloads: 1281 KiB