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

Calculating dependencies ... done!
Dependency resolution took 1.87 s (backtrack: 0/20).

[ebuild  N     ] sys-libs/mtdev-1.1.7::gentoo  295 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     ] x11-libs/xcb-util-0.4.1::gentoo  262 KiB
[ebuild  N     ] x11-libs/xcb-util-image-0.4.1::gentoo  283 KiB
[ebuild     U  ] app-crypt/gpgme-2.2.0:1/45.0::gentoo [2.0.1-r1:1/45.0::gentoo] USE="-common-lisp -static-libs -test -verify-sig" 1389 KiB
[ebuild  N     ] x11-libs/xcb-util-cursor-0.1.6::gentoo  267 KiB
[ebuild  N     ] dev-libs/double-conversion-3.4.0:0/3::gentoo  USE="-test" 6871 KiB
[ebuild  N     ] dev-libs/md4c-0.6.0::gentoo  USE="md2html -test" 263 KiB
[ebuild  N     ] dev-cpp/gpgmepp-2.2.0:0/7::gentoo  USE="-test -verify-sig" 122 KiB
[ebuild  N     ] dev-libs/libevdev-1.13.7::gentoo  USE="-doc -test" 462 KiB
[ebuild  N     ] x11-misc/xkeyboard-config-2.48::gentoo  USE="-test" 931 KiB
[ebuild  N     ] x11-libs/libxkbcommon-1.13.2::gentoo  USE="X -doc -static-libs -test -tools -wayland" 1215 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     ] dev-qt/qtbase-6.11.2-r2:6/6.11.2::gentoo  USE="X concurrent dbus gui libinput network nls opengl sql sqlite ssl udev widgets xml (zstd) -accessibility -brotli -cups -custom-cflags -eglfs -evdev -gles2-only -gssapi -gtk -icu -io-uring (-journald) -libproxy -mysql -oci8 -odbc -postgres -renderdoc -sctp -syslog -test -tslib -vulkan -wayland" 49398 KiB
[ebuild  N     ] dev-qt/qttools-6.11.2:6/6.11.2::gentoo  USE="assistant linguist opengl qdbus widgets (zstd) -custom-cflags -designer -distancefieldgenerator -gles2-only -kmap2qmap -pixeltool -qdoc -qml -qmlls -qtattributionsscanner -qtdiag -qtplugininfo -vulkan" LLVM_SLOT="22 -17 -18 -19 -20 -21" 9992 KiB
[ebuild  N     ] dev-qt/qttranslations-6.11.2:6/6.11.2::gentoo  USE="-custom-cflags" 1652 KiB
[ebuild  N     ] app-text/poppler-26.09.0:0/164::gentoo  USE="cairo cxx gpg harfbuzz jpeg jpeg2k lcms png qt6 tiff utils -boost -cjk -curl -debug -doc -introspection -nss -test -verify-sig" 1994 KiB
[ebuild  N     ] app-text/diffpdf-2.1.3-r4::gentoo  90 KiB

Total: 19 packages (1 upgrade, 18 new), Size of downloads: 76957 KiB

The following USE changes are necessary to proceed:
 (see "package.use" in the portage(5) man page for more details)
# required by app-text/diffpdf-2.1.3-r4::gentoo
# required by =app-text/diffpdf-2.1.3-r4 (argument)
>=app-text/poppler-26.09.0 qt6