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

Calculating dependencies ... done!
Dependency resolution took 0.96 s (backtrack: 0/20).


The following USE changes are necessary to proceed:
 (see "package.use" in the portage(5) man page for more details)
# required by gnome-extra/gnome-shell-extensions-48.3::gentoo
# required by =gnome-extra/gnome-shell-extensions-48.3 (argument)
>=gnome-base/libgtop-2.41.3 introspection
# required by gnome-extra/gnome-shell-extensions-48.3::gentoo
# required by =gnome-extra/gnome-shell-extensions-48.3 (argument)
>=app-accessibility/at-spi2-core-2.60.7 introspection
# required by gnome-extra/gnome-shell-extensions-48.3::gentoo
# required by =gnome-extra/gnome-shell-extensions-48.3 (argument)
>=gnome-base/gnome-menus-3.38.1 introspection
# required by gnome-extra/gnome-shell-extensions-48.3::gentoo
# required by =gnome-extra/gnome-shell-extensions-48.3 (argument)
>=gui-libs/libadwaita-1.9.4 introspection
# required by gnome-extra/gnome-shell-extensions-48.3::gentoo
# required by =gnome-extra/gnome-shell-extensions-48.3 (argument)
>=media-libs/clutter-1.26.4-r2 introspection
# required by gnome-extra/gnome-shell-extensions-48.3::gentoo
# required by =gnome-extra/gnome-shell-extensions-48.3 (argument)
>=media-libs/graphene-1.10.8-r1 introspection
# required by gnome-extra/gnome-shell-extensions-48.3::gentoo
# required by =gnome-extra/gnome-shell-extensions-48.3 (argument)
>=x11-libs/gtk+-3.24.52 introspection
# required by gnome-extra/gnome-shell-extensions-48.3::gentoo
# required by =gnome-extra/gnome-shell-extensions-48.3 (argument)
>=x11-libs/pango-1.58.2 introspection
# required by gnome-extra/gnome-shell-extensions-48.3::gentoo
# required by =gnome-extra/gnome-shell-extensions-48.3 (argument)
>=x11-wm/mutter-50.5 introspection

!!! The ebuild selected to satisfy ">=x11-wm/mutter-3.32[introspection]" has unmet requirements.
- x11-wm/mutter-50.5::gentoo USE="(xwayland) -bash-completion -debug -devkit -elogind -gnome -gtk-doc -introspection -screencast (-selinux) -sysprof (-systemd) -test" INPUT_DEVICES="-wacom" VIDEO_CARDS="-nvidia"

  The following REQUIRED_USE flag constraints are unsatisfied:
    exactly-one-of ( elogind systemd )

  The above constraints are a subset of the following complete expression:
    devkit? ( screencast ) gtk-doc? ( introspection ) exactly-one-of ( elogind systemd ) test? ( screencast )

(dependency required by "gnome-extra/gnome-shell-extensions-48.3::gentoo" [ebuild])
(dependency required by "=gnome-extra/gnome-shell-extensions-48.3" [argument])