utf does map a sequence of code points to a sequence of bytes like the other utfs but unlike them there is more than one valid way to represent a peice of text in utf and its output is designed to be used directly in internet mail essentially it was a case of recognising that utf quoted printable insanely inefficiant encoding and doing it better by designing a single process for the entire task from a registration and mail header point of view utf is considered to be a character set e g its listed at