The Top Left Half Bracket symbol (⸢). Copy and paste it, or use its Unicode, HTML, and CSS codes.
More from Punctuation.
The quickest way is to copy ⸢ from this page and paste it anywhere. You can also insert it with its Unicode, HTML, or alt code listed above.
⸢ is U+2E22 (decimal 11810).
Use ⸢ in HTML to render ⸢ on a web page.
On Windows you can type it with Alt+11810 (hold Alt and enter the number on the numeric keypad).
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