Optional Mode Line Display Display Vars
ASCII printing characters (octal codes 040 through 0176) in Emacs buffers are displayed with their graphics. So are non-ASCII multibyte printing characters (octal codes above 0400).
Some ASCII control characters are displayed in special ways. The newline character (octal code 012) is displayed by starting a new line. The tab character (octal code 011) is displayed by moving to the next tab stop column (normally every 8 columns).
Other ASCII control characters are normally displayed as a caret
^') followed by the non-control version of the character; thus,
control-A is displayed as `
Non-ASCII characters 0200 through 0377 are displayed with octal escape
sequences; thus, character code 0243 (octal) is displayed as
\243'. However, if you enable European display, most of these
characters become non-ASCII printing characters, and are displayed using
their graphics (assuming your terminal supports them).
See Single-Byte European Support.