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

Calculating dependencies  .. . ... done!
[ebuild     UD~] app-shells/mpv-bash-completion-3.3.13::gentoo [9999::bonespirit] USE="luajit" 20 KiB

Total: 1 package (1 downgrade), Size of downloads: 20 KiB
>>> Verifying ebuild manifests

>>> Jobs: 0 of 1 complete, 1 running                Load avg: 2.52, 2.06, 1.70
>>> Emerging (1 of 1) app-shells/mpv-bash-completion-3.3.13::gentoo
>>> Jobs: 0 of 1 complete, 1 running                Load avg: 2.52, 2.06, 1.70
>>> Installing (1 of 1) app-shells/mpv-bash-completion-3.3.13::gentoo
>>> Jobs: 0 of 1 complete, 1 running                Load avg: 2.82, 2.14, 1.73
>>> Jobs: 0 of 1 complete                           Load avg: 2.83, 2.16, 1.74
>>> Jobs: 1 of 1 complete                           Load avg: 2.86, 2.20, 1.76

>>> Auto-cleaning packages...

>>> No outdated packages were found on your system.

 * GNU info directory index is up-to-date.