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

Calculating dependencies ... done!
Dependency resolution took 1.49 s (backtrack: 0/20).

[ebuild     U  ] sys-apps/sandbox-2.51::gentoo [2.46::gentoo] USE="nnp" 444 KiB

Total: 1 package (1 upgrade), Size of downloads: 444 KiB