control character
A character in a text stream that does not represent a written symbol but instead controls formatting, transmission, or device behavior (e.g., newline, tab, escape). Used in computing and telecommunications.
A newline is one of the control characters.
This file contains control characters, so it doesn't display correctly.
特殊文字 (special character) is a broader term that includes symbols, punctuation, and non-alphabetic characters, while 制御文字 specifically refers to non-printing characters that control devices or formatting.
Compound of 制御 (control) and 文字 (character). A straightforward technical term with no unusual etymology.