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

Calculating dependencies ... done!
Dependency resolution took 0.97 s (backtrack: 0/20).

[ebuild  N     ] sci-libs/m4ri-20250128-r1:0/1::gentoo  USE="openmp png -debug" CPU_FLAGS_X86="sse2" 519 KiB
[ebuild  N     ] sci-libs/m4rie-20250128::gentoo  USE="-debug" 433 KiB

Total: 2 packages (2 new), Size of downloads: 951 KiB