that's specific to your os it renders in os emoji colors iirc.

I’ve always seen emoji being stripped on HN, so it’s very surprising to see colors for once

	▲	culi 4 hours ago \| parent \| next [-]
		They've always been stripped for me as well. This "emoji" actually appears black for me however. I think the reason its not stripped is because it's actually "U+2665 : BLACK HEART SUIT {valentine}" which predates the emojis. Lots of fonts and OSes will render these older unicode symbols as emojis
	▲	sylware 4 hours ago \| parent \| prev [-]
		Well, in theory, with proper UTF-8 support you don't need to filter out anything. Unsupported unicode code points are just rendered using a place holder.