[compressedgas]

For example for this story one would place the number 40952952 from the URL https://news.ycombinator.com/item?id=40952952 at the end of the given URL such https://hnrss.org/item?id=40952952

[wruza]

javascript:(_=>{location.href=location.href.replace("news.ycombinator.com","hnrss.org")})();

This is a bookmarklet for it. Add it to bookmarks and click on it after opening a HN thread.