Not sure what's going on here. but I looked at the tomli ebuild and wanted to see what .pyc files it was wanting to install.  So I re-emerged tomli only to get this error:

>>> Emerging (1 of 1) dev-python/tomli-2.0.1::python-modules-kit
 * tomli-2.0.1.tar.gz BLAKE2B SHA512 size ...                                                 [ ok ]
>>> Unpacking source...
>>> Unpacking tomli-2.0.1.tar.gz to /var/tmp/portage/dev-python/tomli-2.0.1/work
>>> Source unpacked in /var/tmp/portage/dev-python/tomli-2.0.1/work
>>> Preparing source in /var/tmp/portage/dev-python/tomli-2.0.1/work/tomli-2.0.1 ...
>>> Source prepared.
>>> Configuring source in /var/tmp/portage/dev-python/tomli-2.0.1/work/tomli-2.0.1 ...
>>> Source configured.
>>> Compiling source in /var/tmp/portage/dev-python/tomli-2.0.1/work/tomli-2.0.1 ...
 * python3_7: running distutils-r1_run_phase distutils-r1_python_compile
python3.7 setup.py build -j 8
/usr/lib/python3.7/site-packages/setuptools/dist.py:726: UserWarning: Usage of dash-separated 'build-base' will not be supported in future versions. Please use the underscore name 'build_base' instead
  % (opt, underscore_opt)
/usr/lib/python3.7/site-packages/setuptools/dist.py:726: UserWarning: Usage of dash-separated 'build-platlib' will not be supported in future versions. Please use the underscore name 'build_platlib' instead
  % (opt, underscore_opt)
/usr/lib/python3.7/site-packages/setuptools/dist.py:726: UserWarning: Usage of dash-separated 'build-purelib' will not be supported in future versions. Please use the underscore name 'build_purelib' instead
  % (opt, underscore_opt)
/usr/lib/python3.7/site-packages/setuptools/dist.py:726: UserWarning: Usage of dash-separated 'build-scripts' will not be supported in future versions. Please use the underscore name 'build_scripts' instead
  % (opt, underscore_opt)
/usr/lib/python3.7/site-packages/setuptools/dist.py:726: UserWarning: Usage of dash-separated 'dist-dir' will not be supported in future versions. Please use the underscore name 'dist_dir' instead
  % (opt, underscore_opt)
Traceback (most recent call last):
  File "setup.py", line 7, in <module>
    packages=setuptools.find_packages(),
  File "/usr/lib/python3.7/site-packages/setuptools/_init_.py", line 153, in setup
    return distutils.core.setup(**attrs)
  File "/usr/lib/python3.7/distutils/core.py", line 108, in setup
    _setup_distribution = dist = klass(attrs)
  File "/usr/lib/python3.7/site-packages/setuptools/dist.py", line 463, in _init_
    for k, v in attrs.items()
  File "/usr/lib/python3.7/distutils/dist.py", line 292, in _init_
    self.finalize_options()
  File "/usr/lib/python3.7/site-packages/setuptools/dist.py", line 836, in finalize_options
    for ep in sorted(loaded, key=by_order):
  File "/usr/lib/python3.7/site-packages/setuptools/dist.py", line 835, in <lambda>
    loaded = map(lambda e: e.load(), filtered)
  File "/usr/lib/python3.7/site-packages/pkg_resources/_init_.py", line 2464, in load
    self.require(*args, **kwargs)
  File "/usr/lib/python3.7/site-packages/pkg_resources/_init_.py", line 2487, in require
    items = working_set.resolve(reqs, env, installer, extras=self.extras)
  File "/usr/lib/python3.7/site-packages/pkg_resources/_init_.py", line 777, in resolve
    raise DistributionNotFound(req, requirers)
pkg_resources.DistributionNotFound: The 'tomli>=1.0.0' distribution was not found and is required by the application
 * ERROR: dev-python/tomli-2.0.1::python-modules-kit failed (compile phase):
 *   (no error message)
 * 
 * Call stack:
 *     ebuild.sh, line   93:  Called src_compile
 *   environment, line 2964:  Called distutils-r1_src_compile
 *   environment, line 1239:  Called _distutils-r1_run_foreach_impl 'distutils-r1_python_compile'
 *   environment, line  453:  Called python_foreach_impl 'distutils-r1_run_phase' 'distutils-r1_python_compile'
 *   environment, line 2591:  Called multibuild_foreach_variant '_python_multibuild_wrapper' 'distutils-r1_run_phase' 'distutils-r1_python_compile'
 *   environment, line 2076:  Called _multibuild_run '_python_multibuild_wrapper' 'distutils-r1_run_phase' 'distutils-r1_python_compile'
 *   environment, line 2074:  Called _python_multibuild_wrapper 'distutils-r1_run_phase' 'distutils-r1_python_compile'
 *   environment, line  841:  Called distutils-r1_run_phase 'distutils-r1_python_compile'
 *   environment, line 1230:  Called distutils-r1_python_compile
 *   environment, line 1099:  Called esetup.py 'build' '-j' '8'
 *   environment, line 1620:  Called die
 * The specific snippet of code:
 *       "${@}" || die "${die_args[@]}";
 * 
 * If you need support, post the output of `emerge --info '=dev-python/tomli-2.0.1::python-modules-kit'`,
 * the complete build log and the output of `emerge -pqv '=dev-python/tomli-2.0.1::python-modules-kit'`.
 * The complete build log is located at '/var/tmp/portage/dev-python/tomli-2.0.1/temp/build.log'.
 * The ebuild environment file is located at '/var/tmp/portage/dev-python/tomli-2.0.1/temp/environment'.
 * Working directory: '/var/tmp/portage/dev-python/tomli-2.0.1/work/tomli-2.0.1'
 * S: '/var/tmp/portage/dev-python/tomli-2.0.1/work/tomli-2.0.1'>>> Failed to emerge dev-python/tomli-2.0.1, Log file:>>>  '/var/tmp/portage/dev-python/tomli-2.0.1/temp/build.log' * Messages for package dev-python/tomli-2.0.1: * ERROR: dev-python/tomli-2.0.1::python-modules-kit failed (compile phase):
 *   (no error message)
 * 
 * Call stack:
 *     ebuild.sh, line   93:  Called src_compile
 *   environment, line 2964:  Called distutils-r1_src_compile
 *   environment, line 1239:  Called _distutils-r1_run_foreach_impl 'distutils-r1_python_compile'
 *   environment, line  453:  Called python_foreach_impl 'distutils-r1_run_phase' 'distutils-r1_python_compile'
 *   environment, line 2591:  Called multibuild_foreach_variant '_python_multibuild_wrapper' 'distutils-r1_run_phase' 'distutils-r1_python_compile'
 *   environment, line 2076:  Called _multibuild_run '_python_multibuild_wrapper' 'distutils-r1_run_phase' 'distutils-r1_python_compile'
 *   environment, line 2074:  Called _python_multibuild_wrapper 'distutils-r1_run_phase' 'distutils-r1_python_compile'
 *   environment, line  841:  Called distutils-r1_run_phase 'distutils-r1_python_compile'
 *   environment, line 1230:  Called distutils-r1_python_compile
 *   environment, line 1099:  Called esetup.py 'build' '-j' '8'
 *   environment, line 1620:  Called die
 * The specific snippet of code:
 *       "${@}" || die "${die_args[@]}";
 * 
 * If you need support, post the output of `emerge --info '=dev-python/tomli-2.0.1::python-modules-kit'`,
 * the complete build log and the output of `emerge -pqv '=dev-python/tomli-2.0.1::python-modules-kit'`.
 * The complete build log is located at '/var/tmp/portage/dev-python/tomli-2.0.1/temp/build.log'.
 * The ebuild environment file is located at '/var/tmp/portage/dev-python/tomli-2.0.1/temp/environment'.
 * Working directory: '/var/tmp/portage/dev-python/tomli-2.0.1/work/tomli-2.0.1'
 * S: '/var/tmp/portage/dev-python/tomli-2.0.1/work/tomli-2.0.1'

The actual files that tomli installed were:

 * Contents of dev-python/tomli-2.0.1:
/usr
/usr/lib
/usr/lib/python3.7
/usr/lib/python3.7/site-packages
/usr/lib/python3.7/site-packages/tomli-2.0.1-py3.7.egg-info
/usr/lib/python3.7/site-packages/tomli-2.0.1-py3.7.egg-info/PKG-INFO
/usr/lib/python3.7/site-packages/tomli-2.0.1-py3.7.egg-info/SOURCES.txt
/usr/lib/python3.7/site-packages/tomli-2.0.1-py3.7.egg-info/dependency_links.txt
/usr/lib/python3.7/site-packages/tomli-2.0.1-py3.7.egg-info/top_level.txt
/usr/share
/usr/share/doc
/usr/share/doc/tomli-2.0.1
/usr/share/doc/tomli-2.0.1/README.md.bz2