Install this version:
emerge -a =kde-plasma/plymouth-kcm-6.6.4
If this version is masked, you can unmask it using the autounmask tool or standard emerge options:
autounmask =kde-plasma/plymouth-kcm-6.6.4
Or alternatively:
emerge --autounmask-write -a =kde-plasma/plymouth-kcm-6.6.4
# Copyright 1999-2026 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2
EAPI=8
KFMIN=6.22.0
QTMIN=6.10.1
inherit ecm plasma.kde.org xdg
DESCRIPTION="KDE Plasma control module for Plymouth"
HOMEPAGE="https://invent.kde.org/plasma/plymouth-kcm"
LICENSE="GPL-2+"
SLOT="6"
KEYWORDS="~amd64 ~arm64 ~loong ~ppc64 ~x86"
IUSE=""
DEPEND="
>=dev-qt/qtbase-${QTMIN}:6[gui,widgets]
>=dev-qt/qtdeclarative-${QTMIN}:6
>=kde-frameworks/karchive-${KFMIN}:6
>=kde-frameworks/kauth-${KFMIN}:6
>=kde-frameworks/kconfig-${KFMIN}:6
>=kde-frameworks/kcoreaddons-${KFMIN}:6
>=kde-frameworks/ki18n-${KFMIN}:6
>=kde-frameworks/kio-6.22.1:6
>=kde-frameworks/knewstuff-${KFMIN}:6
>=kde-frameworks/kwidgetsaddons-${KFMIN}:6
sys-boot/plymouth
"
RDEPEND="${DEPEND}
>=kde-frameworks/kcmutils-${KFMIN}:6
>=kde-frameworks/kirigami-${KFMIN}:6
"
BDEPEND=">=kde-frameworks/kcmutils-${KFMIN}:6"
>=dev-qt/qtbase-6.10.1:6[gui,widgets] >=dev-qt/qtdeclarative-:6 >=kde-frameworks/karchive-6.22.0:6 >=kde-frameworks/kauth-:6 >=kde-frameworks/kconfig-:6 >=kde-frameworks/kcoreaddons-:6 >=kde-frameworks/ki18n-:6 >=kde-frameworks/kio-6.22.1:6 >=kde-frameworks/knewstuff-:6 >=kde-frameworks/kwidgetsaddons-:6 sys-boot/plymouth
>=dev-qt/qtbase-6.10.1:6[gui,widgets] >=dev-qt/qtdeclarative-:6 >=kde-frameworks/karchive-:6 >=kde-frameworks/kauth-:6 >=kde-frameworks/kconfig-:6 >=kde-frameworks/kcoreaddons-:6 >=kde-frameworks/ki18n-:6 >=kde-frameworks/kio-6.22.1:6 >=kde-frameworks/knewstuff-:6 >=kde-frameworks/kwidgetsaddons-:6 sys-boot/plymouth >=kde-frameworks/kcmutils-6.22.0:6 >=kde-frameworks/kirigami-:6
>=kde-frameworks/kcmutils-6.22.0:6