Rocket Validator integrates the W3C Validator HTML checker into an automated web crawler.
According to the HTML specification, text must not contain control characters other than space characters.
In particular, the control character
escapes the Unicode control character “CARRIAGE RETURN” are not allowed.
An alternative is using the character reference
which escapes the Unicode control character “LINE FEED” that is defined to be a space character, so it’s allowed in HTML text.