Replace non-printable characters, e.g., zero-width spaces, with a visible symbol.
Replace non-printable characters, e.g., zero-width spaces, with a visible symbol ❖ (U+2756).
Only formatting characters (\p{Cf}) ^1 are included.
Its detection range is much wider than the Firefox addon ZeroWidth Detection ^2, as the addon only tests four specific characters ^3.
I didn't find a Chrome counterpart.
