Vertical Right Parenthesis

Because it closes asides in text written top to bottom.

Chinese, Japanese and Korean can be set in vertical columns, read from the top down and from right to left. Many Japanese novels, manga and newspapers are printed this way, and so are many books in Taiwan. In a vertical column the brackets turn 90 degrees: the opening ︵ arches over the aside and ︶ cups underneath it.

Modern software usually rotates an ordinary parenthesis by itself when text is set vertically. ︶ exists as a separate character for compatibility with older East Asian character sets that stored the brackets ready-turned.

What does ︶ mean in a text face?

Usually a closed eye: calm, sleepy, smug or sulking.

In kaomoji, faces built from characters and read upright, ︶ is a lowered eyelid. The mouth sets the mood: (︶︿︶) looks glum or fed up, (︶︹︺) is an annoyed pout, and (︶ω︶) is content or a little smug. A face with ︶ eyes says the sender has their eyes shut on something, happily or not.

It is a text character, not an emoji, so its look depends on the font. Some fonts draw it small or off-centre, which can make a face look lopsided.