The Mozilla MDN documentation for XMLDocument
includes the following note — emphasis mine:
The
XMLDocument
interface represents an XML document. It inherits from the genericDocument
and does not add any specific methods or properties to it: nevertheless, several algorithms behave differently with the two types of documents.
The linked spec says something similar:
A document is said to be an XML document if its type is "xml"; otherwise an HTML document. Whether a document is an HTML document or an XML document affects the behavior of certain APIs.
I can find no information on what behaves differently, though. Is this enumerated anywhere?