What ␚ means
It pictures SUB, a control code used for substitution.
ECMA-6, an early character-encoding standard, published its first edition in 1965. ASCII-1967 assigned SUB to control position 1/10 in ASCII, an early text-encoding standard.
A receiver could use SUB for a character judged invalid or erroneous. In the CP/M and MS-DOS era, some text-handling systems treated the same control value as an end-of-file (EOF) marker. ␚ is the visible picture of that control; it does not perform the substitution itself.
Is ␚ the same as Ctrl-Z?
No. Ctrl-Z targets SUB, not this visible picture.
In ASCII-oriented input, Ctrl-Z represents the invisible SUB control (U+001A), though the application decides what the keystroke does. U+FFFD, �, is a separate replacement character used when text cannot be decoded or converted; it is not another picture of SUB.
Technical and diagnostic; it reads like control-code notation in a data dump or protocol note.
Ctrl-Z can trigger an app command or end-of-file behavior; it is not the visible ␚.
Don't confuse it with
2Questions people ask
1Why does the substitute symbol look different?
Fonts can vary the control picture's box, slash, and lettering proportions. Unicode's chart gives a reference drawing; compare the character identity or your tool's legend if the difference matters.
How to type ␚
␚\241ACodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.