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

Calculating dependencies ... done!
Dependency resolution took 1.03 s (backtrack: 0/20).

[ebuild  N     ] acct-group/motion-0-r3::gentoo  0 KiB
[ebuild  N     ] acct-user/motion-0-r3::gentoo  0 KiB
[ebuild  N     ] media-video/motion-4.5.1-r4::gentoo  USE="sqlite -ffmpeg -mariadb -mysql -postgres -v4l -webp" 837 KiB

Total: 3 packages (3 new), Size of downloads: 837 KiB