U+241A "␚" Symbol for Substitute Unicode Character

U+241A "␚" Symbol for Substitute is a graphical representation of the control character with code point 26 in the C0 control code set, originally defined in ASCII as the Substitute character, or SUB. This character was historically used in data transmission and storage to indicate that a preceding character or block of data should be removed or replaced, often as a way to correct errors or signal that a sequence is invalid. The "␚" glyph is part of the Unicode "Control Pictures" block, which provides visible symbols for nonprintable control codes, allowing users to display and discuss these commands in text and technical documentation without ambiguity.