What ｟ means
It opens a paired enclosure. Read the text between ｟ and ｠ as enclosed material. Use （） for routine Chinese, Japanese, and Korean parenthetical text unless a source specifies this white-parenthesis form.
Its history is typographic. In 2000, a Unicode committee record says related white-parenthesis glyphs were adjusted to map to those in Japan's JIS X 0213 character standard. A 2001 Unicode discussion explains that CJK punctuation was designed for fixed-width slots, with each character taking the same horizontal space, and discusses a CJK white-parenthesis pair.
Why does ｟ look like two parentheses?
A typeface can draw one character with a doubled outline. Unicode records this as the common glyph variant. It also links this form with ⸨⸩ and the width-related white-parenthesis pair ⦅⦆; these are connected forms, but they are distinct characters.
For routine CJK parenthetical text, use （）. Reserve ｟ for a source-faithful or specialized typographic distinction.
Specialized punctuation for source-faithful typesetting; use ordinary （） for routine CJK parentheses.
For ordinary CJK parentheses, use （）; ｟ may render as two marks.
Don't confuse it with
1Combination ideas
1Questions people ask
1Is ｟ the same as ((
No. ｟ is one character; a typeface can draw it with a doubled outline. The two marks `((` are two ordinary opening-parenthesis characters.
How to type ｟
｟\FF5FCodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.