Ah that's nice, thank you. Sorry I mis-rewrote when I tried to correct what was copied from Twitter. It addeded some extraneous "https://" too.

  javascript:if (!location.href.match('ycom')) {location.href='https://news.ycombinator.com'};if (typeof e!=='undefined') e.style.background='#c0c0c0';e=Array.from(document.querySelectorAll('.age%20a:not(.seen)')).sort().at(-1);e.style.background='#ff0';e.classList.add('seen');e.scrollIntoView({behavior:"smooth",block:"center",inline:"nearest"});{}

I see, that {} at the end is intentional, as you described in another comment.

And accessing the variable e before assigning it a value, now I see that probably serves a practical purpose too.

Did you write this? If so, why did you add the "{}" at the end? Also, can't you use newlines in bookmarklets?

Yes, I wrote it.

The {} prevents the code from evaluating to a value that the browser then would use as the new value for the DOM, overwriting the existing page.

Try bookmarking javascript:123 and see what happens when you click it.

Bookmarklets are URLs, so a newline in the code would be urlencoded as %0A. So you could do:

javascript:alert(1)%0Aalert(2)

But I would prefer:

javascript:alert(1);alert(2)