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

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

[ebuild  N     ] dev-cpp/fast_float-8.0.2::gentoo  USE="-test" 119 KiB
[ebuild  N     ] dev-libs/libzip-1.12.1:0/5::gentoo  USE="bzip2 ssl -gnutls -lzma -test -tools -zstd" 795 KiB
[ebuild  N     ] media-libs/lib3mf-2.5.0:0/2::gentoo  USE="-test" 38190 KiB

Total: 3 packages (3 new), Size of downloads: 39102 KiB