HTML5 documents are not XML; this means that tooling that isn't a browser, or isn't 'HTML aware' became excluded. The web 'special cased' itself at this point,

HTML5 documents are not XML; this means that tooling that isn't a browser, or isn't 'HTML aware' became excluded. The web 'special cased' itself at this point, and HTML and common data processing pipelines of the time parted ways, this is my only point.