[xor_]

I've stumbled upon this thread late, and it took me a bit to figure out why the character information from OP's JSON file wouldn't display in Koreader on my Kobo.

Turns out that the data structure for custom JSON files in Worddumb has changed, and in addition to that there was a small bug that prevented showing it in Koreader.

I've edited that JSON file to accomodate the new file structure, and as of the latest Worddumb release, the bug has also been fixed. At least it works now in Koreader on my Kobos. There's still a problem with Kobo's native nickel app.

So, if anyone is still interested, here's the updated file. The unzipped worddumb-custom-x-ray.json file goes into the folder of the Three Body Problem ebook in your Calibre library. Then you can process it with Create X-Ray from the WordDumb plugin.