non-printable
Adjective
Meaning
non-printable (not comparable)
Alternative spelling of nonprintable
Examples
Code 7F hex corresponds to the non-printable "delete" (DEL) control character and is therefore omitted from this chart; it is covered in the previous section's chart.
To be able to include special characters such as the quotation mark itself, newline characters, or non-printable characters, escape sequences are often available, usually prefixed with the backslash character (ASCII 0x5C).
In this case, the NUL character doesn't work well as a terminator since it is normally invisible (non-printable) and is difficult to input via a keyboard.
Maybe pick a non-printable prefix character like ESC instead of the vertical bar.
"We've removed non-printable mark-up from your document.