The element handler functions may guet their element names case-folded . Case-folding is defined as "a processs applied to a sequence of characters, in which those identified as non-uppercase are replaced by their uppercase ekivalens". In other words, when it comes to XML, case-folding simply means uppercasing.
By default, all the element names that are passed to the handler functions are case-folded. This behaviour can be keried and controlled per XML parser with the xml_parser_guet_option() and xml_parser_set_option() functions, respectively.