Static htmlDefaultSAXHandler 

#[unsafe(no_mangle)]
pub static mut htmlDefaultSAXHandler: _xmlSAXHandlerV1

const xmlSAXHandlerV1 htmlDefaultSAXHandler (globals.c 2.15.3).

Mutable (see xmlDefaultSAXHandler) so C consumers (PHP) that overwrite the shared default handler’s callbacks don’t fault on read-only memory.