mutf-8 contains simple pure-python as well as C encoders and decoders for the
MUTF-8 character encoding. In most cases, you can also parse the even-rarer
CESU-8.

These days, you'll most likely encounter MUTF-8 when working on files or
protocols related to the JVM. Strings in a Java .class file are encoded using
MUTF-8, strings passed by the JNI, as well as strings exported by the object
serializer.