Install this version:
emerge -a =dev-python/mutf8-1.0.6# Copyright 1999-2023 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2
EAPI=8
DISTUTILS_EXT=1
DISTUTILS_USE_PEP517=setuptools
PYTHON_COMPAT=( python3_{12..14} )
inherit distutils-r1 pypi
DESCRIPTION="Fast MUTF-8 encoder & decoder"
HOMEPAGE="http://github.com/TkTech/mutf8"
LICENSE="MIT"
SLOT="0"
KEYWORDS="amd64 ~arm64 x86"
IUSE=""
RDEPEND=""
DEPEND="${RDEPEND}"
REQUIRED_USE="${PYTHON_REQUIRED_USE}"