Code point
U+23A1
Glyph appearance depends on your fonts.
U+23A1
SmU+23A1 LEFT SQUARE BRACKET UPPER CORNER is a Unicode 16.0.0 character in the Math Symbol category. It belongs to the Miscellaneous Technical block.
Choose the representation you need, then copy its value.
U+23A1
9121
⎡
⎡
E2 8E A1
23A1
000023A1
%E2%8E%A1
\u23A1
\u23A1
\u23A1
\23A1