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html_frames is incorrect. That link points to a w3schools page about iframes. While the frame tag is deprecated in HTML5, iframe not only is not deprecated; in reality, iframe has three new attributes added by the HTML5 spec.
They've probably redirected it to the iframes page, to correct themselves.
They do have this page though:
So I'm not sure if the W3fools page should link to that instead...?
Fixed frame element link.