https://html.spec.whatwg.org/multipage/parsing.html#parsing-main-inforeign

If the parser was created as part of the HTML fragment parsing algorithm, then act as described in the "any other start tag" entry below. (fragment case)

This part seems to be implemented in Gecko but not Chromium or WebKit.

Demo.

@whatwg/html-parser @mfreed7