Hunspell misdetects a cjk word as English word, and try to correct it. Of course, there's no matching word in the dictionary, resulting linter shows noisy misspelling warnings on cjk words.
This package acts as a fake dictionary to ignore such cjk words.
In short,
Without linter-spell-cjk:
With linter-spell-cjk:
Good catch. Let us know what about this package looks wrong to you, and we'll investigate right away.