This doesn't drive the standards process in any particular direction, this is just a broken implementation that doesn't adhere to the current standard draft!
It sounds overly mischievous though (and I doubt Mozilla will bend), so my bet is that it's a mistake.
> But none of this answers the original question: why do we have an <img> element? Why not an <icon> element? Or an <include> element? Why not a hyperlink with an include attribute, or some combination of rel values? Why an <img> element? Quite simply, because Marc Andreessen shipped one, and shipping code wins.
> That’s not to say that all shipping code wins; after all, Andrew and Intermedia and HyTime shipped code too. Code is necessary but not sufficient for success. And I certainly don’t mean to say that shipping code before a standard will produce the best solution. Marc’s <img> element didn’t mandate a common graphics format; it didn’t define how text flowed around it; it didn’t support text alternatives or fallback content for older browsers. And 17 years later, we’re still struggling with content sniffing, and it’s still a source of crazy security vulnerabilities. And you can trace that all the way back, 17 years, through the Great Browser Wars, all the way back to February 25, 1993, when Marc Andreessen offhandedly remarked, “MIME, someday, maybe,” and then shipped his code anyway.
> The ones that win are the ones that ship.
I'm not convinced it's a mistake, and it wouldn't be the first time a browser maker tried to influence the direction of web.