Code point
U+2143
Glyph appearance depends on your fonts.
U+2143
SmU+2143 REVERSED SANS-SERIF CAPITAL L is a Unicode 16.0.0 character in the Math Symbol category. It belongs to the Letterlike Symbols block.
Choose the representation you need, then copy its value.
U+2143
8515
⅃
⅃
E2 85 83
2143
00002143
%E2%85%83
\u2143
\u2143
\u2143
\2143