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

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

[ebuild  N     ] gui-apps/waypipe-0.9.2-r1::gentoo  USE="-dmabuf -ffmpeg -lz4 -systemtap -test -vaapi -zstd" CPU_FLAGS_X86="avx2 avx512f sse3" 192 KiB

Total: 1 package (1 new), Size of downloads: 192 KiB