I’d forgotten just how exasperating the WordPress forums are. Ask if anyone’s seen a plugin for something, get pointed at a bunch of random functions that also do something different. Ask about elements in an .wxr import/export document, get lectured that “element” isn’t a term for pieces of WordPress code; “element”, of course, is exactly what units in an XML document are called, and what I was talking about. You have to love (no you don’t) when coders are so obsessed with inflicting their pedantry at people they don’t even actually read your question.