The Internet Archive is permitted when the original site or content is unavailable.
Otherwise, HN's rule is to "submit the original source": <https://news.ycombinator.com/newsguidelines.html>
I suppose that might be clarified as "most original or canonical", but Because Reasons HN's guidelines are written loosely and interpreted according to HN's Prime Directive: "anything that gratifies one's intellectual curiosity" <https://news.ycombinator.com/item?id=508153>.