dependency dev-python/python-musicbrainz-ngs changed name to dev-python/python-musicbrainzngs
The ytmdl ebuilds from this overlay depend on dev-python/python-musicbrainz-ngs and package name has changed to dev-python/python-musicbrainzngs in the official tree - it lost the '-' before 'ngs'. This causes an emerge error since it can no longer find python-musicbrainz-ngs.