Lead Developer
The .po files from WP.org are stored in the wp-content/languages/themes folder on your server.
You can also grab the latest GP files which made it so translations can’t break widgets here: https://github.com/tomusborne/GeneratePress
I’ve requested that an editor make the fix a few times with no luck – seems the Japanese team isn’t very responsive.
If I could get someone who speaks/writes Japanese to volunteer I could request that they become an editor.