Code point
U+3010
Glyph appearance depends on your fonts.
U+3010
PsU+3010 LEFT BLACK LENTICULAR BRACKET is a Unicode 16.0.0 character in the Open Punctuation category. It belongs to the CJK Symbols and Punctuation block.
Choose the representation you need, then copy its value.
U+3010
12304
【
【
E3 80 90
3010
00003010
%E3%80%90
\u3010
\u3010
\u3010
\3010