Sometime you will see things like \< or \| in the markdown. A backslash is positioned before a character. This is called " escaping". Its purpose is to enforce a certain interpretation of the escaped character. For example, a human editor may use < and > to indicate a dubious or supplemented reading of a text. However, the software processing the markdown will interpret these characters as tag markers, like <p>. The backslash tells the software to ignore the character.
Newlines are control characters in a character encoding specification like Unicode that signify the end of a line of text and the start of a new one. Several such characters exist. Some of the most widely used are:
CR = carriage return (return to beginning of line) = Macintosh before OSX
LF = line feed (= move down one line) = Unix, macOS
CR LF = a combination of LF and CR = Windows
The Unicode points for these characters are (in hexadecimal notation):
CR = U+000D
LF = U+000A
CR+LF = U+000D followed by U+000A
In certain programming languages, these control characters are handled by escape sequences. In Python, for example, \r represents a carriage return, and \n a line feed. Other languages may have different escape sequences to set, search and replace special characters. The following therefore only applies to BPT:
CR = U+000D = \r
LF = U+000A = \n
CR+LF = U+000D U+000A = \r\n