Install this version:
emerge -a =media-sound/helvum-9999
If this version is masked, you can unmask it using the autounmask tool or standard emerge options:
autounmask =media-sound/helvum-9999
Or alternatively:
emerge --autounmask-write -a =media-sound/helvum-9999
# Copyright 2022 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2
EAPI=8
inherit git-r3 meson
DESCRIPTION="A GTK patchbay for pipewire"
HOMEPAGE="https://gitlab.freedesktop.org/pipewire/helvum"
EGIT_REPO_URI="https://gitlab.freedesktop.org/pipewire/helvum.git"
LICENSE="GPL-3"
SLOT="0"
KEYWORDS="~amd64 ~x86"
RESTRICT="network-sandbox"
DEPEND=">=media-video/pipewire-0.3
>=gui-libs/gtk-4.12.2"
RDEPEND="${DEPEND}"
BDEPEND=">=sys-devel/clang-3.7
dev-build/meson
virtual/rust"
>=media-video/pipewire-0.3 >=gui-libs/gtk-4.12.2
>=media-video/pipewire-0.3 >=gui-libs/gtk-4.12.2
>=sys-devel/clang-3.7 dev-build/meson virtual/rust