`char.def` is copied from [mecab-ipadic v2.7.0](https://taku910.github.io/mecab/).
`lex.csv`, `matrix.def`, and `unk.def` are copied from `tests` in
[sudachi.rs](https://github.com/WorksApplications/sudachi.rs/tree/develop/sudachi/tests/resources).
We have appended the last two rows in `unk.def` from the original source.