=item XML::Parser::Expat::load_encoding(ENCODING)

Load an external encoding. ENCODING is either the name of an encoding or
the name of a file. The basename is converted to lowercase and a '.enc'
extension is appended unless there's one already there. Then, unless
it's an absolute pathname (i.e. begins with '/'), the first file by that
name discovered in the @Encoding_Path path list is used.

(...) The only reason users should use this function is to
explicitly load an encoding not contained in the @Encoding_Path list.