Licensing of ZhConversion data files is complicated.
In theory, MW repo doesn't exclude these from GPL, but the files as a whole are pieced together from many sources with different licenses:
- Some character-to-character mapping are from the Unihan database, which is in the public domain.
- Some items are from Chinese Wikipedia, licensed under CC BY-SA 3.0.
- Some items are directly contributed through Git, so they are under GPL.
Therefore, I don't think the tables can really be licensed under GPL. But in reality, no one is sure about how to license them. Since a community consensus which allows fair-uses of this table was reached, I still decided to put these in the library for convenience and consider this fair-use. If there are any updates on this, feel free to open an issue or dmca this repo. If something goes south, you can still provide your own tables.
https://github.com/wikimedia/mediawiki/blob/master/includes/languages/data/ZhConversion.php