Code point
U+235B
Glyph appearance depends on your fonts.
U+235B
SoU+235B APL FUNCTIONAL SYMBOL JOT UNDERBAR is a Unicode 16.0.0 character in the Other Symbol category. It belongs to the Miscellaneous Technical block.
Choose the representation you need, then copy its value.
U+235B
9051
⍛
⍛
E2 8D 9B
235B
0000235B
%E2%8D%9B
\u235B
\u235B
\u235B
\235B