@georgieboygorgeous georgeous You can match the target of a link in CSS¹, so you could in theory do this with a CSS-modification extension like Stylus², although it's on you to come up with how to mark the link. (I think CSS can add text to the page these days, but I haven't looked at that. But if you can, there are lots of options. Giant thumbs-down emoji, throwing up person emoji, pile of poop emoji, ...)
¹ https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/Selectors/Attribute_selectors#syntax
² https://addons.mozilla.org/en-US/firefox/addon/styl-us/
