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

Calculating dependencies ... done!
Dependency resolution took 1.44 s (backtrack: 0/20).

[ebuild  N     ] dev-build/b2-5.5.3::gentoo  USE="-examples" 1198 KiB
[ebuild  N     ] media-libs/glm-1.0.3::gentoo  USE="-test" CPU_FLAGS_X86="avx avx2 sse2 sse3 sse4_1 sse4_2 ssse3" 4490 KiB
[ebuild  N     ] x11-misc/xkeyboard-config-2.48::gentoo  USE="-test" 931 KiB
[ebuild  N     ] dev-libs/libsigc++-2.12.1:2::gentoo  USE="-gtk-doc -test" 4924 KiB
[ebuild  N     ] dev-cpp/nlohmann_json-3.12.0-r1::gentoo  USE="-test" 9452 KiB
[ebuild  N     ] dev-libs/yyjson-0.13.0:0/0.13::gentoo  USE="-doc -test" 1604 KiB
[ebuild  N     ] sys-libs/mtdev-1.1.7::gentoo  295 KiB
[ebuild  N     ] dev-cpp/mm-common-1.0.8::gentoo  277 KiB
[ebuild  N     ] dev-util/wayland-scanner-1.26.0::gentoo  599 KiB
[ebuild  N     ] dev-libs/libevdev-1.13.7::gentoo  USE="-doc -test" 462 KiB
[ebuild  N     ] x11-libs/libxkbcommon-1.13.2::gentoo  USE="X -doc -static-libs -test -tools -wayland" 1215 KiB
[ebuild  N     ] x11-libs/libxkbfile-1.2.0::gentoo  57 KiB
[ebuild  N     ] dev-cpp/glibmm-2.66.8-r1:2::gentoo  USE="-debug -gtk-doc -test" 8396 KiB
[ebuild  N     ] dev-libs/boost-1.91.0-r2:0/1.91.0::gentoo  USE="bzip2 context nls python stacktrace zlib -debug -doc -icu -lzma -mpi -numpy -test -test-full -tools -zstd" PYTHON_TARGETS="python3_14 -python3_12 -python3_13" 199785 KiB
[ebuild  N     ] media-libs/libdisplay-info-0.4.0:0/4::gentoo  USE="-verify-sig" 117 KiB
[ebuild  N     ] sys-auth/seatd-0.9.3-r1:0/1::gentoo  USE="-builtin -elogind (-selinux) -server (-systemd)" 42 KiB
[ebuild  N     ] x11-libs/xcb-util-renderutil-0.3.10::gentoo  256 KiB
[ebuild  N     ] x11-libs/xcb-util-wm-0.4.2::gentoo  279 KiB
[ebuild  N     ] media-fonts/font-util-1.4.2::gentoo  150 KiB
[ebuild  N     ] media-libs/libepoxy-1.5.10-r3::gentoo  USE="X -test" 325 KiB
[ebuild  N     ] x11-libs/libxcvt-0.1.3::gentoo  10 KiB
[ebuild  N     ] x11-libs/libXfont2-2.0.9::gentoo  USE="bzip2 truetype -doc" 468 KiB
[ebuild  N     ] dev-libs/wayland-protocols-1.49::gentoo  USE="-test" 148 KiB
[ebuild  N     ] dev-libs/wayland-1.26.0::gentoo  USE="-doc (-selinux) -test" 0 KiB
[ebuild  N     ] dev-libs/libinput-1.32.0:0/10::gentoo  USE="-doc -lua -test" INPUT_DEVICES="-wacom" LUA_SINGLE_TARGET="lua5-4" 944 KiB
[ebuild  N     ] x11-apps/xkbcomp-1.5.0-r2::gentoo  243 KiB
[ebuild  N     ] gui-libs/wf-config-0.11.0:0/0.11::gentoo  USE="-test" 45 KiB
[ebuild  N     ] x11-base/xwayland-24.1.14::gentoo  USE="-libei (-selinux) (-systemd) -test -unwind -xcsecurity" 1278 KiB
[ebuild  N     ] gui-libs/wlroots-0.20.2:0.20::gentoo  USE="X drm libinput session x11-backend -lcms -liftoff -verify-sig -vulkan -xcb-errors" 686 KiB
[ebuild  N     ] gui-wm/wayfire-0.11.0-r1:0/0.11::gentoo  USE="X dbus gles3 nls openmp -test" 1021 KiB
[ebuild  N     ] gui-libs/wayfire-plugins-extra-0.11.2:0/0.11::gentoo  63 KiB

Total: 31 packages (31 new), Size of downloads: 239745 KiB

The following USE changes are necessary to proceed:
 (see "package.use" in the portage(5) man page for more details)
# required by gui-wm/wayfire-0.11.0-r1::gentoo
# required by gui-libs/wayfire-plugins-extra-0.11.2::gentoo
# required by =gui-libs/wayfire-plugins-extra-0.11.2 (argument)
>=gui-libs/wlroots-0.20.2 x11-backend

 * In order to avoid wasting time, backtracking has terminated early
 * due to the above autounmask change(s). The --autounmask-backtrack=y
 * option can be used to force further backtracking, but there is no
 * guarantee that it will produce a solution.