All the text files containing Japanese characters in this repository are encoded in ISO-2022-JP. This is because ISO-2022-JP encoded texts are most suitable for the traditional pTeX engine.
The bundle is maintained on GitHub: https://github.com/texjporg/ptex-base
If you have issues, please let us know from the above page.
The bundle may be distributed and/or modified under the terms of the 3-clause BSD license (see LICENSE).
Japanese TeX Development Community