This definitely leads me to believe that you don't have much experience with modern web frameworks. The meaning of "component" in modern web development is pretty consistent. You can think of a component as a custom HTML element (though they can be much more complex than built-in HTML elements). In fact, if you are using HTML Web Components, then your component literally is a custom HTML element. But the metaphor works even when generating HTML server-side: If you can reference a piece of UI by name, and pass it attributes, and it packages up some HTML/CSS/JavaScript in a reusable fashion, then it's a component.

Your question is slightly nonsensical, because components are not a design language, and it's not something you can see by looking at a rendered web page. To know whether Hacker News is using components, I would need to look at the source code, because components are a programming paradigm.

If you're asking me to comb through HN's JavaScript to see if they use that paradigm, well, no thank you.