Not been writing XML parsers, but I remember Nick Bradbury the creator of the FeedDemon fame wrote about it a lot 'back in the days',

* https://nickbradbury.com/2006/09/21/fixing_funky_fe_1/

* http://nick.typepad.com/blog/2004/01/feeddemon_and_w.html

* https://en.wikipedia.org/wiki/FeedDemon