Code point
U+298F
Glyph appearance depends on your fonts.
U+298F
PsU+298F LEFT SQUARE BRACKET WITH TICK IN BOTTOM CORNER is a Unicode 16.0.0 character in the Open Punctuation category. It belongs to the Miscellaneous Mathematical Symbols-B block.
Choose the representation you need, then copy its value.
U+298F
10639
⦏
⦏
⦏
E2 A6 8F
298F
0000298F
%E2%A6%8F
\u298F
\u298F
\u298F
\298F