libexpat1-dev binary package in Ubuntu Focal i386

 This package contains the header file and development libraries of
 expat, the C library for parsing XML. Expat is a stream oriented XML
 parser. This means that you register handlers with the parser prior
 to starting the parse. These handlers are called when the parser
 discovers the associated structures in the document being parsed. A
 start tag is an example of the kind of structures for which you may
 register handlers.

Source package