[hobnail]

For our potentially nascent Grand High Sorcerer, the reason for my statement, "but xhtml is not the same thing as html (even though it may look the same)" is because a lot of software uses files with an xml syntax, but if those files were fed to a validating xml parser it would reject them. So they're using what you could think of as a faux or pseudo xml.

The xml syntax is very rigorous; for example, it's used for data transport by the stock exchanges, banks, etc. You definitely wouldn't want them using yaml or json for that.