That's because kitty correctly prints not an emoji motorboat, but rather a text motorboat; the \U0001F6E5 defaults to text presentation and that is why east_asi

That's because kitty correctly prints not an emoji motorboat, but rather a text motorboat; the \U0001F6E5 defaults to text presentation and that is why east_asian_width returns 'N'. You can get the fancy one with print("\U0001F6E5\uFE0Fhello"). However, the bug that the post alludes to is that not all terminals override the east_asian_width to 'W' when they see "\uFE0F". For example on gnome-terminal the "h" overlaps with the right half of the boat.