Code point
U+2571
Glyph appearance depends on your fonts.
U+2571
SoU+2571 BOX DRAWINGS LIGHT DIAGONAL UPPER RIGHT TO LOWER LEFT is a Unicode 16.0.0 character in the Other Symbol category. It belongs to the Box Drawing block.
Choose the representation you need, then copy its value.
U+2571
9585
╱
╱
E2 95 B1
2571
00002571
%E2%95%B1
\u2571
\u2571
\u2571
\2571