This article is underwhelming. Despite being in English, it links to a Japanese Wikipedia article. The English Wikipedia article has all the same info as this post and more: en.wikipedia.org/wiki/Ghost_characters

tl;dr: some Japanese kanji from older encodings were carried forward into new ones. But some of those characters were difficult or impossible to identify. Most were archaic place names or transcription errors.

I like the article. Interesting subject, well written and it has the perfect lenght.

I asked AI to tranlate it and it correctly identified the characters are ghost characters.

I asked Google Translate which said it was simplified Chinese “The company is committed to providing high-quality products and services.”

lol