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

Calculating dependencies ... done!
Dependency resolution took 1.07 s (backtrack: 0/20).

[ebuild  N     ] dev-libs/nspr-4.40::gentoo  USE="-debug" 986 KiB
[ebuild  N     ] sys-boot/gnu-efi-4.0.4::gentoo  USE="(-custom-cflags)" 240 KiB
[ebuild  N     ] dev-libs/nss-3.131::gentoo  USE="utils -cacert -test -test-full" CPU_FLAGS_X86="avx2 sse3" 85996 KiB
[ebuild  N     ] app-crypt/pesign-116::gentoo  118 KiB

Total: 4 packages (4 new), Size of downloads: 87339 KiB