Out of IE, Firefox and Chrome (and presumably also Safari, given its shared history with Chrome, but I can't test it), curiously enough IE(11) was the only one

Out of IE, Firefox and Chrome (and presumably also Safari, given its shared history with Chrome, but I can't test it), curiously enough IE(11) was the only one [1] to allow properly selecting and copying generated content, i.e. text added via the CSS "quotes:" or "content:" properties. Firefox/Gecko at least does a workaround for handling quotation marks (though it is rather hacky, because it always copies them as a standard ASCII double quotation mark instead of whatever typographically more appropriate character the page might actually be using, and it always adds both opening and closing quotation marks even if the selection only straddles one of them), but gives up for free-form text added via "content:", and Blink and presumably also Webkit don't handle that kind of content at all. [1] I've already forgotten how the old Edge based on EdgeHTML handled that scenario.