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

Calculating dependencies ... done!
Dependency resolution took 1.01 s (backtrack: 0/20).

[ebuild  N     ] dev-util/wayland-scanner-1.26.0::gentoo  599 KiB
[ebuild  N     ] dev-libs/wayland-1.26.0::gentoo  USE="-doc (-selinux) -test" 0 KiB
[ebuild  N     ] dev-libs/wayland-protocols-1.49::gentoo  USE="-test" 148 KiB
[ebuild  N     ] gui-apps/swayidle-1.9.0::gentoo  USE="-elogind (-systemd) -verify-sig" 14 KiB

Total: 4 packages (4 new), Size of downloads: 759 KiB