What does a leading `\x` mean in a Python string `\xaa`

Question

What is difference between \'aa\' and \'\\xaa\'? What does the \\x part mean? And which chapter of the Python documentation covers thi

Answer 1

That's unicode character escaping. See "Unicode Constructors" on PEP 100

Answer 2

The leading \x escape sequence means the next two characters are interpreted as hex digits for the character code, so \xaa equals chr(0xaa), i.e., chr(16 * 10 + 10) -- a small raised lowercase 'a' character.

Escape sequences are documented in a short table here in the Python docs.