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

Calculating dependencies ... done!
Dependency resolution took 1.11 s (backtrack: 0/20).

[ebuild  N     ] dev-libs/libsigc++-2.12.1:2::gentoo  USE="-gtk-doc -test" 4924 KiB
[ebuild  N     ] dev-cpp/mm-common-1.0.8::gentoo  277 KiB
[ebuild  N     ] dev-cpp/glibmm-2.66.8-r1:2::gentoo  USE="-debug -gtk-doc -test" 8396 KiB
[ebuild  N     ] x11-libs/libXtst-1.2.5::gentoo  USE="-doc" 285 KiB
[ebuild  N     ] x11-libs/libXres-1.2.3::gentoo  USE="-doc" 263 KiB
[ebuild  N     ] app-accessibility/at-spi2-core-2.60.7:2::gentoo  USE="X -dbus-broker -dbus-glib -gtk-doc -introspection (-systemd) -test" PYTHON_TARGETS="python3_14 -python3_12 -python3_13" 587 KiB
[ebuild  N     ] dev-libs/atk-2.46.0::gentoo  USE="-introspection" 0 KiB
[ebuild  N     ] dev-cpp/atkmm-2.28.4::gentoo  USE="-gtk-doc" 723 KiB

Total: 8 packages (8 new), Size of downloads: 15453 KiB